[Autumn]

Changing its identity would be re-tooling it for a different purpose or use, changing it in a way that makes it less useful in your eyes is not at all changing its identity, I think you are mistaken in that regard. No its quite as simple as moving the effects to be less abusable by another mechanic in MG that makes the effective momentum sink cost of Null Shell under specific circumstances 3m instead of 6m, while changing it to be the overcharge effect would erase that specific momentum cost and also cause such a powerful null to have a cooldown associated to it as well. (As well as removing double tapping the charged effect under specific circumstances)

Changing the amount of statuses being nulled would draw away from the effect which has never really been regarded as strictly being too powerful in this thread? Only that the effect is terrifyingly oppressive in its current state and the ease of application and lack of drawback, if anything the amount of statuses it dispels helps combat the whole filler status thing, no other nulls in the game dispel as many statuses as null shell does.