For Skaven, in a style I'd enjoy, it'd likely be to shift to multiple smallish Clanrat units with weapon teams, then replace some Stormfiends with a Hell Pit Abomination, swap out Verminlord for some Jezzails and other goodness, maybe some Warlock Engineers who can Warp Lightning like crazy and channel to add more power dice. It's possible, at least. That's with the models I have, anyway.
I'll probably try the Ogres this weekend. But first I've been challenged to a 2v2 40K match where I know I'll be facing Murderface McMurderpants, a Stormfang, Thunderwolf Cavalry, the psychic power Endurance, Death Company in a Land Raider, and Dante, just as a starting point. (No points for guessing those two are also the two Chaos Warriors players who won't stop putting MoN on everything even after being told it automatically makes an army a "beatstick" army. Best part was when one of them used such an army against a guy trying to learn how to play, and that guy was using Bretonnians.)