I don't have issues with Legacy servers, it comes down more to, why join a Legacy server when they provide non-Legacy servers? After all, I'm not a Legacy player.
As far as the RP servers go... I could actually see the benefits there. That being, I'm assuming there's a generally more friendly atmosphere there, and not a dozen people standing outside any given dungeon spamming "CLASS LFG DUNGEON NAME" ad nauseam.
But there too, I'm not a roleplayer. So my choice would be a non-legacy non-RP server simply on account of my not being either of those things is all.