I rarely have a problem with being unable to finish a public quest. There are plenty of people around and I've never had a problem joining an open party. Don't often experience lag either, except when those Order bastards AOE like hell.

There is some class imbalance but they're updating those kinds of things very regularly.

For how much I've been enjoying this game, it'll be super awesome once they've gotten to the point where they've fixed the release bugs and are adding new features.