Well. I think the "stomp" can actually be used at any time, even mid-air? That would certainly make it quite strong.
But from how it was introduced and how it usually works in these games, I assumed:
- You can only use it when standing on the ground
- If you’re not on the ground, the input might be "buffered" and you end up making a stomp as soon as you hit the ground, which might be bad
I suspect also that you’re basically invulnerable while stomping? That would again make it quite strong and masheable. But it’s not how these things usually works in serious(tm) games.