This is far more like TF originally was than what TF2:Brotherhood of Arms (or whatever it was) was supposed to be. It's clear that they scrapped that project entirely (which is really no big new news: we've all known it was vaporware for years), and there's no sense in crying over it now that that game direction has been done to death. At this point, returning to what made TF so fun is a welcome direction.
At first I was with everyone else whining "oh, wtf?!?" about the style change, but honestly, speechrut is right. If TF2 is going to be remotely successful it needs to be more different from its competition.
That said, I do see this being mostly a TF (and I pray God not TFC) rehash, but we'll see. I like the models and animations (the demo's demo toss), and I surprisingly like the style as well. For those who say TF was "realistic" I can't really agree...sniper bullets that disintegrated a body in one shot, medics healing people with the swipe of an axe and poisoning people the same way, soldiers and heavies that survive multiple rocket shots, maps that never felt like they were anywhere but in fantasy (castles, futuristic forts, arena-style forts....ok, ok, Border1 was sort of realistic
While I don't simply want a TF re-hash I'll gladly take it over the other games available right now. TF has needed a new engine ever since the Q1 source was released and the nail was put in that coffin. I don't think TF ever died -- it was just forced into early retirement.