So with HOTS I have been excited about it for awhile as a zerg player the new units look good and so far they have not disappointed me in the days I have watched.
In sc2 as it is every zerg I know absolutely hates the zvp match up, this isn't due to balance (some thing it is) but not even talking about balance it is one of the dullest mu's in the game (PvP imo is worse). I think most people can agree that zvp is really not a fun match up to watch, it literally consists of 3 scenarios.
Either protoss 2 base all ins and wins or they lose or the game goes into a "macro" game where both players get a deathball and whoever engages the best either by protoss getting a good vortex, or whatever the game is over once that deathball dies 99% of the time.
Literally no excitement in the match up. Look at zvt and you don't get that. Even though zerg is still going for that fast hive, there is normally aggresion for a good part of it where the terran is dropping, splitting and not sitting grabbing their own deathball.
Now the one thing I hate about playing zerg in general is the fact that you pretty much have to go hive and you can do lair aggression, but if you don't do damage 9 times out of 10 you are dead. Normally it's defend - get hive - get ultras/broodlords - then you can start being aggressive.
Watching HOTS even in this early stage has made even watching zvp a lot more fun then WoL zvp. zvt is still fun to watch as expected when it's not warhound killing everything .
But the main thing I want to touch on is I feel the new units for zerg (especially the swarm host) have actually made a good impact on gameplay right now. It's obviously very early in the beta and for all I know in a few months/weeks/days/etc this could be different whether swarmhosts become underpowered due to nerfs or players figure out how to counter them who knows it can and obviously will change, but hopefully for the better where swarm hosts will almost always be a standard in zvp/zvt like lurkers are standard in bw zvt/zvp.
I have watched some 20+ minute zvp's and I was entertained watching it. Swarm hosts attacking the front while a few are harassing an expansion. Or my personal favorite was when a zerg (stephano or idra can't remember which) had a swarm host contain on a protoss and was using hydra/overseer to snipe observers so protoss couldn't see the swarm hosts. This reminded me so much of bw zvp in that aspect where it's like "oh shit if he gets the observer no detection!".
Now I want to clarify I don't want sc2 to be like bw, but I just wanted to point out it brought a lot mroe action is more so my point.
The viper I have seen in action and I have also really liked the function of the unit. I watched a zvz where the zerg with vipers used blinding cloud and then fungeled the roach/hydra while attacking with ling/ultra. This made ultra/ling a lot stronger (obviously) and was really fun to see some epic holds where a zerg was attacking up a ramp only to get that blinding cloud and not being able to kill the ultra's (that was vs sheth).
I like the abduct ability, a lot of people don't like it obviously but this is a good ability that I am glad and hope stays in the game. It is very satisfying for me to see zergs using it pretty well in abducting colossi/immortals and while I haven't seen to many vipers due to the hive tech the little I have seen has made me extremely happy with both units (and the buff to blinding cloud in terms of effecting everything will be nice in zvp :D).
I am also happy for the most part with the terran units as well. I feel the spider mine isn't being utilized enough and although I know players say it's week I think it's got great potential. For example mines can be used to deny ling runby's in the third when you are attacking and I am surprised I haven't seen that used very much. Although I have heard terran players keep forgetting spider mines exist because they are to busy making warhounds.
I in general like the design of the battle hellion and feel this alone makes mech a lot more viable even if the warhound was removed. Correct me if I am wrong but from what I know one of the biggest issues with mech in current WoL is chargelot/immortal that just decimates mech. With the battle hellions now chargelot's aren't as good and I imagine mech is a lot more viable with just that change, immortals still have hardened shield but I have a feeling mech is still good. Of course this is just theory as terrans are just making warhounds so other then the warhound I actually quiet like the new units or transformation for hellions for terran.
Unfortunately for protoss I feel they got really screwed in hots. I'm sorry but their new units are just absolutely stupid. The oracle is just a weak joke of a unit, it can block minerals which is annoying but it's just so dumb. I don't know what kind of things they could have gave toss but the fact that tempest/oracle are the best they could come up with is really disappointing.
Before I knew about the new units I was curious what protoss could get as I really couldn't think of anything that would make them better as a race that wouldn't make their deathball stronger or something and idk very disappointed with the protoss units and I feel bad for toss, but nothing can be done. I do not see blizzard adding or removing any of the new units no matter how bad they are.