I think if you're going to borrow rogues from another existing franchise, you're usually better off getting the lower profile ones.
Firstly because you have more freedom to do whatever you want with them (unlike say Doom), and secondly because there's at least a CHANCE you can snag them away from the other rogues gallery (like Daredevil snagging Kingpin from Spider-Man). A Morlun or an Adversary potentially can be more of a long term loan from the Spider-Man or X-Men franchises because their relatively low profile characters in very very large rogues galleries. But a Kang will never really leave the Avengers rogues gallery because hes' probably second only to Ultron as far as being their most common opponent.
So rather than the Kree or Skrulls, if you go with say the Dire Wraiths, you have something you can potentially weave into the mythos. They're part of the ROM's rogues gallery, but it's not like he'll be needing them anytime soon. If you mine marvel for stuff no one else is using, you can potentially expand the mythos in a more meaningful way than an otherwise cool one shot appearance might be.