Arcaus: the xp tapers off pretty hardcore compared to needed xp as you get closer to 60. Even fully rested the entire time and completing every single sidequest in every new zone, about a million xp shy of 59 (I ran a few dungeons and got it later, though) with quests giving about 40k xp each. That's a minimum of 20ish quests short, and I even ran some dungeons 2-3 times while I was leveling for other people. Completing most dungeons starting with Sohm Al will give you 160k-ish+ xp, and the roulettes were rewarding like 200k for completing before any other bonuses were added in.
I haven't really had any problems on gilg, as it appears with the heavy instancing of some areas they don't really need to gate the server nearly as much.