Any time i mention numbers or stats they are rough guesses to give a general idea of my thinking.
Terran changes:
-Raven Rework-
Zerg and protoss have the mothership core and queen, both units built from the main base buildings that provide a slight combat advantage but mainly a bunch of utility. I wanted to extend this to terran to give them more options in the early game, especially vs zerg,
Ravens now are "attached" to orbital commands. When you build an orbital, you get a one-use ability on that orbital to call in a raven. Costs 200/150. The Raven shares an energy pool with it's parent orbital. When you attach a raven to an orbital the regen rate of the shared pool is increased.
Seeker missile now requires research again at a starport techlab. Damage and radius slightly increased as ravens will be less massable lategame.
The whole idea behind this change is for terrans to have the option of sending a raven out with their hellion groups to keep queens occupied, this will provide more early game micro and back-and-forth situations. Good placement of PDDs will be very pivotal.
Also i feel ravens are generally not seeing their full potential so making them easier to access throughout the game imo can only be good.
A potential problem with this change is making attacks similar to the 1-1-1 vs protoss too strong, this can be solved by changing the mothership core attack from projectile to beam.
-Tank changes-
Ideas completely stolen (from Barrin i think) but still good
Tanks now 2 supply
Can now overkill (i.e smart-firing removed)
There's a whole other blog on the reasons for this but basically makes terran the positional race again and allows for cool micro
-Anti-air options changes-
Viking and Thor anti air roles basically switched and tuned to match unit costs.
Thors now have a long range single target missile attack, firing faster and further(maybe?) than the viking's because thors cost more.
Vikings have a splash attack with shorter range (same as phoenix). Phoenixes no longer light to compensate for change in pvt air-to-air dynamic.
Yes this is very similar to bw and blizzard has a reluctance to make any changes that make sc2 too much like bw but imo that's the wrong approach.
This makes mech vs P slightly different as Thors can now take out collosus until army sizes get too big and thors get trapped in the back due to their size at which point you'll want vikings or ravens. Carrier and maybe tempest play should be more viable, as well as phoenix vs mech.
Versus zerg thors vs broodlords should be slightly in broodlord's favour but not overwhelmingly, additionally groups of vikings can punish clumping of broods.
Zerg changes
-Midgame options-
Basically the infestor needs to be tuned down and the hydra and muta tuned up to allow for there to be an actual choice of what lair tech route to take. David Kim already said they're planning on doing this but here's my thoughts anyway.
Mutalisk: You want to build mutas to allow you transition to the lategame, they should serve to keep the enemy back in his base or low on economy until you have an army that can put up a decent fight. They shouldn't be able to engage and decently sized army straight up.
HP reduced slightly, damage increased slightly. This makes a group of mutas stronger against small groups of units but weaker against big groups, giving them more power to control where the opponent sends his army.
Passive ability, when a mutalisk takes damage it's speed is increased by 40% for 3 seconds. More running away power but no extra attacking power.
Hydralisk
Size, cost, hit points and damage all significantly increased. Range upgrade now included as standard. Speed off creep and burrowed hp regen increased to equal speed roaches. Gains extra damage when fighting in melee using it's clawblades (or whatever they are).
New ability:Cull the Weak - the hydralisk pounces on and devours a nearby wounded zerg ground unit, gaining hit points equal to the target's current hp. No energy cost or cooldown but the animation should be like 2-3 game seconds (maybe with some cool squealing noises). Massive units are immune. Requires research at Hydra Den
My thoughts with the hydra was that basically it should give the midgame zerg army more oomph while being totally cool at the same time because hydras are awesome and have had a rough time of it in Wings of Liberty. So i wanted the hydra to be similar to the immortal and siege tank in terms of size and cost (though it should probably be a little more expensive than both due to larva mechanic) and the kind of presence/influence it has on a battlefield; by which i mean how much it forces your opponent to change his tactics with regards to engaging your army.
It's ability i'm rather proud of as it opens up a lot of (imo) cool plays.
It allows you to essentially exchange one unit for part of a hydralisk at the cost of losing the unit and the time it takes to eat it. This forces your opponent to try to focus your hydras first. (I think it would be cool if ghosts were a viable option against hydras but that would mean either changing Snipe which would have other problematic ramifications or making the hydra psionic which doesn't fit the lore and flavour of the unit.) Another aspect of the ability is the pounce. This can be used as an escape or a distance-closer to allow the hydra the use of it's melee attacks which are more powerful, but at the cost of placing it in more danger in a more forward position. I think lots of cool micro could potentially occur with this while not making the unit too overpowered. Something to note about the ability is that it requires a wounded target, this is to discourage using it outside of a battle situation - if the hydra is not immediate danger it's better to burrow it - and also to place some (probably needed) limits on the available micro options and power of the ability.
I kept it as works on all zerg units rather than just friendly ones just because it can't exactly mess up zvz balance.
Having fewer, more expensive units is perhaps not especially zergy but i think it's ability brings it some cool zerginess flavour while establishing it firmly as above the roach in the food chain.
Infestor
Yes, the lord of Imba himself. It's time to nerf this badboy.
I'm of the opinion that infestor/brood should be extremely powerful considering the gas investment that goes into the composition and the best way to balance it is to extend the midgame to make it harder to reach. Nevertheless it shouldn't beat a similar costing army all the time though and ideally lategame battles should be very long and drawn out with lots of micro on both sides.
Current role: anti-deathball, anti-air, lategame power (good way to convert vespene into firepower), harrass potential
Current problems: Fungal limits micro, spamming beachballs looks silly, neural a bit hit or miss, essential to build every matchup all the time. Critical mass too easy to obtain.
As to the essential to build problem, i think the muta and hydra changes should deal with that as well as of course the addition of the viper and swarm host.
Fungal Growth - changed to Fungal Spores: Creates an cloud of fungal spores that slowly expands. Damages enemy units for 12 hp per second or 12% of max hp/s to armoured and heals friendly units for 7% of max hp/s. Lasts 15 seconds. Starts about the size of a spine crawler and expands to about the size of a hatchery within 10 seconds. Affects air and ground. Costs ~75% of max energy, Pathogen Glands reworked to increase energy regen rather than starting energy.
So this is a way to give the infestor some muscle without making nerds cry. You can cast it right in the middle of an enemy ball and they have to split or retreat or just fight through the damage, or you can pre-cast on an area to delay a push or hold off an army while you're busy getting into position or whatever.
Because the counter is basically to retreat, it makes setting up flanks much more important. The idea is that fungal will force a retreat but you won't be able to rely on it to outright kill any kind of mobile army unless you have a surround.
The healing of friendly units will have very little effect on anything but ultras, broods, roaches and the new hydras. My aim here is to increase the strength of an ultralisk-based army, increase the power of a roach/hydra composition in the later game and stop blinking stalkers directly under broods becoming an autowin for toss.
Infested Terrans: Removed.
They're basically an energy dump for when you have all the fungals you need but still have energy left over. Frankly i don't think this is good design, and the wild spamming to coat the map in them just feels wrong and inelegant somehow, as does rebinding your mousewheel to leftclick with a 3rd party program just to spam them out faster. A big issue at the moment is that once you have enough infestors for all the fungals you need, it's still a good idea to keep making them. Although ITs are being redesigned visally in HotS i don't think there will be or should be a place for infestors that aren't going to fungal, that money should go on Vipers or broods or ultras or something. i.e. Overmaking infestors should be a bad idea and punishable by your opponent.
If you want to do some burrow-move harrass then the new fungal will do the job just fine.
Neural Parasite: Redesigned to Umbilical Nutrients, no upgrade at infestation pit required.
At the moment NP is not really taken all that seriously although it can be useful against mech and some protoss armies if the infestor can be kept safe. I think the max hp/second drain of Fungal Spores deals with zerg's problems versus the large power units you'd use NP on so neural needs a redesign.
Umbilical Nutrients is an energy channel spell, the infestor can pass it's own energy to another friendly psionic unit.
This isn't meant to be a powerhouse of a spell, but it does mean you can recharge your Vipers out in the field and if you make a bunch of infestors to defend a push they won't have enough energy upon spawning due to the pathogen glands change i proposed, this ability slightly alleviates that situation as maybe you make 5 infestors, then between them they can fungal 2 or 3 times.
-Corruptor changes-
Auto-attack removed
Replaced with a suicide ability that causes heavy aoe damage (in a small radius) over time. The corruptor latches on to an air unit (or collosus) with it's tentacles (think The Matrix) and expells noxious fumes into it. Deals 150 damage over 5 seconds to the primary target and surrounding air units. The corruptor becomes untargetable during the process and dies when it ends.
This keeps it a decently powerful unit but now you can't take wounded corruptors and turn them into broodlords, which currently strongly negates any air to ground tech switch potential. This also means if the opponent keeps making air units or collosus you have to keep making corruptors or deal with them some other way. The explosion damage isn't instant as i feel that would be too powerful against units which normally would reliably get some attacks off before dying.
-Creep Changes-
Enemy (non-zerg) units on creep now take very slight damage over time. Creep recedes faster when unsupported by tumours.
I feel that zerg is the race most vulnerable to all-ins, cheeses and timing attacks and needs just a little more defensive power and reward for map control. The damage should be % of max hp based so marines aren't overly punished. I'm thinking numbers along the lines of if you have half the map coated in creep, then all the units in a push are on about 75% hp when they arrive at your natural. It just makes creep spreading and clearing that little bit more important. Remember i also proposed that raven change which would help.
Protoss Changes
-Collosus Changes-
Direction of beam changed from a dual tangential sweep to a single radial line. Damage of beam significantly increased, speed of beam decreased, can now be micro'd out of.
When i first started playing sc2 i kept moving my units out the collosus' beams but still getting owned because that makes no difference. These changes allow for more positional play from protoss as you'll want to have your collosus on the flanks (finally that cliff walking has a use) and more micro from your opponents. This can only be good. The damage is now less reliable so has been increased to compensate for balance.
-Warp Gate/Gateway Unit Changes-
The warp gate is a cool idea gone horribly horribly wrong. It means that protoss is incredibly reliant on timing attacks and all-ins for success. PvT is not so bad but PvZ is really in the shithole at the moment.
Build times of non-warped gateway units decreased to equal current WG cooldown times.
Warp Gate research is now researched from the Twilight Council and costs 200/200.
Blink is now researched from the Cybernetics Core.
These changes would hopefully keep warpgates good for mid and lategame useage, defending against air and drops etc, while eliminating the really harsh timings that frankly aren't that fun to watch and replacing them with some cool micro from blink stalker harrass.
The focus for protoss should be more about unit control than build orders and timings (imo anyway).
ok i spent far too long on this, seem to be distracted from revising pretty easily ^^
might update in future or remove it if i read it tomorrow when sober