That worries me too. Vergil seems to have a slower fighting style (wrongly worded, but I'll explain), and I have no idea if I'll like any new weapons they give him (I'm worried there will be weapons that are meant to be spammed).
What I mean by slow, is that it seems like he makes short, and quick attacks with pauses inbetween. The Yamato from previous games can be used effectively, or spammed. In DMC1 it was just a reskin of Alastor, so it was spammed by Sparda... but in DMC3 Vergil uses his weapons in bursts. He'll attack, retreat, attack, retreat... etc.
I'm tired, and I'm not sure where I'm going with this point.... but what I'm saying is, is that I like the whole short burst style of fighting. Instead of being Dante and just running in slashing everything, I'd like Vergil to be more effective as a character that stands back and jumps in and out of an enemies face to take care of them quickly.
Feel free to point out any flaws in my logic here.