1. Death ball plays
2. Lack of interesting units that would promote unique plays
So rather than suggesting specific fixes to these problems I would like to point out a direction that is in my opinion optimal for solving these problems.
Death ball plays
Some time ago I re-played all the 90' old RTS which when I was younger I struggled to beat.
One of those games was KKND2, a game where similarly to StarCraft there are 3 races.
The game is however pretty imbalanced, but there are some lessons to be learnt anyway.
I realized that if I try to just mass a lot of units a press a-move I don't automatically win.
You see in KKND2 there are a lot of units and even static defences with a solid splash damage.
So rather than a-moving a huge army you are rewarded for tactical plays.
Doing drops to strategic location, attacking weakly defended locations, small air groups...
If you think about it in SC-Broodwar compared to SC2 you had a lot of powerful splash damage units and abilities - Siege Tanks, Spider mines, Irradiate, Lurkers, Plague, Reavers, Psionic Storm, Corsairs, Valkyries, Devourers.
Now in SC2 there are a few aswell, but their use is somewhat specialized.
Siege Tanks aren't very popular, you occasionaly see some cool Heat seeking missiles used, zerg has the fungal which is more of mass stun than damage spell, so you are left with like a few units/abilities that do splash and are used Colossus, Thor, widow mine and storm.
So no wonder that protoss deathballs are so strong, there is no zerg or terran ground splash to counter.
No wonder that protoss struggles with mass multalisks, there is no solid AOE to counter them.
Cool units
Blizzard has taken a path to design cool units.
What makes a cool unit:
- attack/abilities/usage that is somewhat innovative
- micro potential -> skill ceiling
But what I see in SC2 micro is just hit & run and positioning.
I would like to take another game example here.
I used to play Dota for years and later on I switched to League of Legends.
If you look at LoL ability design you see a pattern - abilities with cast/spawn delay, abilities which need to be aimed, projectiles which travel at speed, abilities which do damage over time to area...
Basically the abilities need to be aimed correctly by the caster, require some sort of prediction of the enemy behavior. But the enemy still has choices to dodge, avoid or reduce the damage taken.
If we look at Broodwar again we will see that a lot of abilities are exactly like that:
Irradiate damage can be reduced if you move the affected unit away from the group.
Emp can be slightly dodged.
Spider mines can be slighly dodged also.
Defiler plague cannot be dodged however you may retreat to safety and repair or regenerate(if you aren't protoss that is).
Lurker spines can be dodged!
Revear shots damage can be greatly reduced if you split or move away your units.
Storms can be completely dodged or damage reduced if you move away.
At the same time SC2 has:
Widow mines cannot be dodged.
Emp is instant and cannot be dodged.
Fungal growth after HOTS can finally be dodged although chain fungal still cannot be microed against.
Storm can be slighlty avoided however compared to SC1 storm it is instant spawn with almost instant damage spell so much less avoidable.
Colossus damage cannot be avoided.
Only heat seeking missile can be dodged!
Conclusion
SC2 LOTV needs much much more splash damage in units or in abilities.
SC2 LOTV needs abilities that have spawn delays, require aiming or do damage over long periods of time in order to introduce new forms of micro and increase the skill ceiling.