You've missed a fair bit but it won't take long to get back into it. As far as your questions go I'll do my best, based on my personal opinion:
Server: Harbinger (especially good for Pub side PvP)
Class balance: Of the ones you have you can't go wrong with Shadow or Vanguard at the moment.
Ranked: Can't give much info here... I enjoy team ranked, and occasionally solo just for a laugh. Depends on who else is queuing at the time.
Regular WZ's Queues: On Harbinger it's really good. Don't think I've ever had to wait more then 10 minutes, most pops are under a minute or 2.
As far as class balance goes; that's a bit of a long debate really. You already have some of the slightly stronger classes so it will come down to your play style and personal preference. I really like my Shadow, Scoundrel and Commando at the moment. Vanguard has some ridiculous burst, Sentinel is still great in a group. I think Gunslinger has been a little neglected lately... Couldn't really tell you since I don't have one.
Guardians and Sages (balance spec) are probably the fotm right now and a bit too easy mode. I have a Sorc and don't bother playing it atm since it feels a little too strong in PvP. Without the challenge it gets boring quickly.
Personally I'd lean toward the Vanguard since they're just so much fun and there's a shortage on Harby. Anyway I'm sure others will have something to add...
Welcome back!