It's fine. Any longer range and it'd be OP. My usual dueling style is very aggressive, but against good kickers I have to change how I play, and even then the really good ones can trick you sometimes. For other people, kick is what it should be- a very situational tool. You shouldn't be kicking around like Jackie Chan in a game with swords and shit.
Im not saying you should be kicking around like jackie chan, having a kick range that is basically equal to the length of the leg when its extended in game is what is needed. if you look, that isnt very long at all.
And by aggressive playstyle im guessing you mean facehugging hiltslashing, in which ofcourse you dont want kick extended, cos it counters your own playstyle.
It wouldnt make it OP at all, it can already be a death sentence for even the best kickers, stops you moving/turning, making people easily get behind you for a hit. and half the time that happens, the kicker see's there foot go through the others players body as they ran around.
