Welcome back.
It's hard to answer your first question because to be perfectly realistic, PvP hasn't been seriously balanced ever and the very nature of PvP works on abusing highly imbalanced skills and stats. So maybe you mean to use a different word, because a balanced class is generally an ineffective PvP class. Perhaps you want to say strongest, weakest, most versatile, most useful etc. to describe what you are looking for.
In terms of P2W, I honestly don't think so. When I think of P2W I think that investing a lot of money nets you an insurmountable advantage that is inaccessible to F2P players. RO2's "P2W" comes from the severe level of randomness that can go into perfecting end-game gears, and that's where you might be held hostage for your money. You can still access a lot of the necessary stuff if you put in the time to farm for it, so unless you're short on time, you're rarely feeling disadvantaged. A lot of the broken stuff are systemic, rather than item based, so money doesn't affect it. The marginal advantage that perfect items get you is rather minimal, from a stats point of view, but for some people, it's more fun to not look at those numbers.
I hope this helps, and although I'm not nearly as proficient in the PVP scene, this generalization should form a good enough picture for you.