It's kinda hard for me to join you as I think I deleted my chars on Skullcrusher eventually (were only 18 & 21 anyway). I do have a lvl 43 shammie on The Maelstrom server which is unplayed atm and could be transferred really (need money for my mount though :p).
And afaik the raid instances in tBC will be 25-man, though they might throw in a few 40-man instances, you never know.
PvP will get a big overhaul with the expansion: no more honor grinding for ranks. Instead you'll be able to accumulate honor over time to get PvP rewards, so even casuals will be able to get good gear eventually without having to play 24/7. They're going to add 1 more BG, all tBC zones have some world PvP objectives and they're also introducing arena matches (2vs2, 3vs3 and 5vs5 iirc) which will have the better PvP rewards. They're also working on some sort of matchmaking service so you won't have a PuG of fresh lvl 60's in green gear vs a team of epixed chars, though it might be mainly for arena matches as they want to intruduce a ladder system, etc.