I got a genius idea: Try him out! Maybe he's not quite so OP as you might think.
Jayce is very strong in dominion and one of my favorite champs due to his versatility and fun kit. But its not like all the other champs suck.
I would contend that Jax is also kind of good in dominion, as is Poppy, Yorick, KZ, Kassadin and quite a few others. I am pretty sure people aren't arbitrarily limiting their use of those champs in the sake of 'fairness'.
Is anyone really saying that Jayce is SIGNIFICANTLY better than Jax, Kass, Yorick?