Remember Killer Instinct? It was an old arcade fighting game in the Street fighter genre. The thing that really set Killer Instinct apart was the combo's. You could get these killer combos of 60+ hits, if you knew how to execute them. As the opposing player, you may as well just walk away once a pro starts into his combo. Sure, they had combo breakers, but even these had to be timed perfectly to get the freak off of you.
My point is, if we buff all the heroes, your going to see more and more unbreakable combo's. Right now in its current build (far from balanced, we know), there are some "killer" combos. For example, take a team of 3 Rooks. All it takes is one of them to get the opposing player with a boulder. Thats it. 5 second stun with a 10 second cooldown. Theoretically, it would onlly take 2 Rooks to perma stun a player or group of players. Not to mention a double hammer slam will kill any character except a beefy rook. I doubt that even that beefy rook would be worth much after 3.
Players want to be in control. They want to feel like they can choose to fight or run at some point in the confrontation. Getting permastunned and dying just because you couldn't dodge the first boulder is going to be very frustrating. Damage over time is one thing, but completely immobilized and unable to act for 5, 10, 15+ seconds is horrifying.
Stuns are extremely powerful, too powerful in this build. Stun duration, cooldown, and the fact that the 3 current demigods all have at minimum 1 stun makes for a frustrating game.
Sure, go ahead and beef the other Demigods. Watch out for killer combos (aka unbeatable). But for the love, nerf all stuns.