I'm sorry, but what you just said gets under my skin like few other things.
The system does NOT make the game.
With the addition of the social skills suchs as diplomacy, bluff, & sense motive, d20 is now just as capable of being a social or political game as the Storyteller system.
I think where people get confused is because the opposite is not true. The Storyteller system isn't even close to being as good at handling combat as the d20 system. Of course, this isn't much of a problem for the WoD games because combat is usually discouraged.
However, I do think the WoD games would be better if it had a more streamlined combat system. Why not?
My point is this:
D20 does a great job with both the martial and social aspects of the game.
Storyteller, while great with the social aspects, does [In my opinion] a very poor job of handling combat.
I see no reason AT ALL not to convert Vempire to d20. The fact is, a great many WoD players look down on d20 because it's first offspring was D&D. Because in the past, the D&D system didn't bother with the social skills, many WoD players still look down on the system and refuse to give it a shot. Now the d20 system has evolved into a true ROLE-playing game, and yet they still refuse to look at it.
Who would have thought that people who pretend to be Vampires and Werewolves would be so close minded.