Seriously, I have a lvl 50 human-only PB and she does just fine in end game content. And she's not even fully IOd yet.
Nova-only seems like it would be really dull and boring to me. For starters you have to take other powers, you can't avoid that. And to use any kind of self buffs you need to drop out of Nova. I mean, give it a go, it can be fun to try things that are outside the box. But honestly I don't think this one is gonna have any legs, no pun intended.