Would you like to put forth some kind of justification for this? I for one am inclined to disagree with you. Apocrypha would be perfect if we wanted to spend a DLC doing fetch quests for books, but otherwise it doesn't seem that cool.
The thing that draws me to Apocrypha is that there is so little known about it. Yes, we know the general layout (endless library full of forbidden knowledge) but there are only like two books that describe it. In each of these books, it doesn't give a very good description, no hints of the enemies that you face inside, no idea if there is Herma-Mora and a palace deeper inside. They only give us the barest explanation of it. The Hunting Grounds in contrast are pretty well explained: Endless fields, forests, and canyons devoted to staying away from Hircine as he finds and kills you. I'm not saying a Hunting Ground DLC would be boring, I would be all for it. But Apocrypha has some much mystery around it that we might actually be able to learn more than going to Hircine's Realm.