[Yossar]

Blood is more or less worthless in combat. Forget about it unless you plan on using your pretender to get some of the bigger blood summons for a nation that normally has trouble getting them.

Death is really only good for spamming and killing undead early on. But don't underestimate the ability of quickness (from boots or the spell) + raise skeletons/dead to allow a pretender to singlehandedly take moderately difficult indies. Later on you get soul vortex, which is nice.

Regeneration from nature is great for preventing your pretender from picking up afflictions. But a lot of pretenders get it naturally and you can get it easily from items, so it isn't quite a necessity.

But what I've seen pretty much agrees with your observations.