I played through undead chapter and want to give some feedback. The campaign is quite good, better than original one. Was fun
Babysitting Setroth is bit annoying. He's slow and not that tough. Standard doom knights seem to be stronger. I've had few times were I was doing well then got "Your character is under attack", "Your character is dead" right after another, because Sethroth ran into some enemies. Most of time I put him in a tower and forgot about him. Ctrl-d ing him allowed me to kill him once without ending level.
New spell system makes magic lot stronger.
Fey ambushes can be horrible because of banshees. Sometimes you would get ambushed by a force with three banshees who would rip right through skeletons, wights(108 magic splash damage is bit much). Luckily I found out strip flesh works on banshees, so that solved that issue.
The generous-greedy perk I don't know about. Some scenarios it helps, others it works against you. Greedy or neutral seems to be the way to go, because if you have more allies than enemies you have mostly already won.
In the temple spider trap most of my troops got stuck in appearing wall. Also weak spiders vs unreachable fire cannons makes one route lot easier than other.