That's just the thing, though. Maybe I'm just a bit older than you in this hobby, but to me the return of Nagash is the 'good old fluff', and the 'good old divisions' were, to me, ever an arbitrary and unwelcome intrusion that had the effect of elevating the pop culture icons of vampires and mummies above the true core of what was distinctive about the undead in the Warhammer World, the liches and necromancers, the mad, decrepit sorcerers of death, and chief among them Nagash.
You wonder if transformers or disney are the biggest influence, where as I look at these models, and the biggest influence I see is the old undead, the true original Warhammer undead. I see 20 year old warhammer aesthetics, I see John Blanche and Wayne England. I see some of the most distinctively warhammery warhammer undead that I've seen in a long time.
Now, of course, to each their own. I'm not saying you're wrong for not liking this stuff, though I do think you're being a touch melodramatic. I really don't think 'Tomb Kings' or 'Vampire Counts' are going anywhere, nor do I believe that the return of my unified 'Old Undead' will outlast this campaign. Things will go back to the good old (bad young) way of things soon enough. But in the mean time, I'm eating it up, because right now I'm feeling the same excitement I felt as I leafed through the 4th edition Undead army book for the first time nearly 20 years ago.