Necromancy options for summoning unique undead bosses?

Now listen very closely... with the reveal of the spirit-walker being able to tame unique beast bosses: it would be really kinda actually fantastic and great... if you just let us do that for undead next. Since we seem to be dead-set on keeping it to three ascendancies per class and therefore likely will never get a necromancer ascendency, I volunteer Lich as tribute to sacrifice a node for this. K bye