I was thinking yeah because it would have to be really weak otherwise to balance it out right? It makes it more risky but maybe there's a sufficient award. Or maybe it's like an empowered ability that changes your heavy melee after ulting or something.
Also I'm thinking it would be like a roundhouse kick or something? Maybe there would be no movement charge so you're stationary, but you cannot be parried?
Maybe to make it a bit more fair you could choose to do the AOE extended heavy melee by inputting the melee button again, though you would also have the option NOT to do the aoe, so you could trick/fake out a enemy sometimes into parrying which would make them be locked in the parry animation so you can shoot/use abilities on them im sure that would be a little annoying but it would be neet non the less