1. Dreds became cross-server at some point under gameforge, I think around mid-end 3.x?
2. It was a mix, but the twinks are hard to deal with for "normal" players since it leaves them at the mercy of other players to come and help them deal with the problem. I'm not sure if handing out free pvp gear is the way to go about it though, but the massive pvp debuff that killed rifting certainly isn't either.
The point about rifting and twinks is going to be a big one for the classic server. Killing rifting killed the game, but when players of the opponent race can effectively lock you out of doing instances/quests on your own home map that's frustrating too.
TBH i dont think PVE players will want to go classic it really going to be the PVP players who loved rifting and having some great fun. Anyone back then who only wanted PVE and cried due to getting killed I don't think they will come back as they know Classic and what it will be.
Yes the buffs and what they did to try and deal with the care bears really did kill a great deal.