Coming to a crash/reboot near you soon:

1) Demons and angels are slightly less dumb in picking actions. They won't tend to keep trying to blind someone who's already blind, for example.

2) Started tweaking devil AI also; this is still far, far, far from done. In particular, they'll do a lot more for conjurers that aren't evil. If you're an orderly neutral conjurer, a devil might be a really good choice once these changes go live. If you're an evil conjurer, not too much has changed here.

3) Devils will be able to deal with groups more effectively. If you're of the "I can't beat one person with a devil, how am I going to handle three?" school of thought/experience, you probably still want to avoid that. I wouldn't say devils have been made good for fighting a group, just less bad.

4) Dimensional hunters (psychic vampire, lost soul, dimensional shambler, etc.) have been adjusted to punish non-archon/fire elemental servitor choices less severely. I'll warn you right now that if this turns out to make them too easy to deal with in the general case (unlikely, but possible) they'll be tweaked back up.

5) Homonculous made marginally better. Yay, homonculous.

I'm probably forgetting something, but I think that's about it. Some of the infrastructure for the above is going to be semi-recycled into building some bad-ass quest skills for a handful of non-conjurer classes. After that I may try to improve devil AI some more.