A potentially good AOE farming spot I discovered recently is also in wetlands, at the Angerfang encampment.

There are around 4 camps where orcs spawn, and normally there are a few quests here, one where you have to kill orcs to gather 8 flags per character which is when I came here. I believe the mobs around level 25ish. I was a bit overleveled already and was blasting through these mobs. Some of the camps are probably 7 or 8 mobs but they're easy to farm with 3 mages.

You can get a decent amount of xp here as well as wool cloth drops.

Running between gnoll camps is also a decent option in wetlands, but I think the angerfang camps are closer together and spawn more/faster.