In my last playthrough I decided to finally try orcs and demons.
Orcs - even with the CW improvements still a bit disappointing (or maybe because of them, I didn't care for the new Adrenaline feat).
But boy, the demons were fun! I dumped executioners after a while (too slow, too expensive, wimpy dmg/lship ratio) and changed them for imps. Best unit ever!
With the Whip of Pain, Assassin Dagger and the awesome strike-and-return ability a thousand imps can wreak some serious havoc.
And the demoness was even more awesome. With Avgares nad the Whip of Pain she almost always killed the whole stack with one strike.
Not that it was necessary after she teleported my Cerberi into enemy ranks - with their three-head strike they cleared it all out in two three rounds.
The only possible weakness - Archdemons. In my view they don't have any useful abilities. Teleportation seems nice, but a hasted demon with "run" is with the enemy in one round as well and with my demoness-cerberi combo it was not really necessary anyway. And halving only sounds cool. Later I only took them for the fights with dragons, it was funny to watch those poor black and red bastards not being able to even touch them
One stack of 15 black dragons did like 22 damage to my Archdemons
So if anyone is also bored with overpowered strategies like black knights, pure ranged or plants with botany-blackthorne-assasin dagger-whip of pain combo, demons are a great entertainingly different team to go with.