You pretty much need a form of AoE sleep, preferably multiple forms of it, to comfortably win. Once you have that, it becomes pathetically easy. (BLU can solo it, for instance; they've got a ton of sleep spells. You might need to stall at some points to recover MP, but again, since Adelheid doesn't actually attack anything, stalling is no problem.) It's definitely one of the easiest of WotG's "escort" battlefields.
Having AoE sleep for Blood of Heroes is... not quite enough, at all. Having done all the WotG content, I can comfortably say that it's probably the hardest fight of all the missions and mission-quests, simply because Excenmille will actively try to get himself killed, and 8 mobs in the battlefield can do a pretty good job of that. It is the only WotG fight that I was never able to solo.