Also... if the Liches are still the Necromancers, just undead, why are they more animal-like? I don't hear them talk, I don't see them doing research or something. All they do all day long is waiting for an intruder to kill (inb4 GAME MECHANICS).
I think that
is just a gameplay mechanic. Afaik there was talk of liches doing stuff humans would normally do too, they are just animal like in-game. That being said, I'd love to see liches playing around with items on an enchanting table if you sneak up instead of just standing there and gazing in the dusty wall.
Or maybe they are just meditating on the immortality of the may bugs.
You didn't destroy the Heart, you just disenchanted it and it disappeared. Vivec, Almalexia, and Sotha Sil were all still alive at the time the Heart was disenchanted. All it did was severe their tie to the Heart and make them mortal. Thus, the Tribunal and Dagoth Ur could be killed. That was the whole point of doing it.
How exactly, if you can kill both Vivec and Almalexia prior to destroying the heart?