I would hope Captain Jack Harkness comes back for the anniversary.
Hell, I'd be happy for him just to turn up at all. Wish Miracle Day had been a better success, then Torchwood could keep goin'...
He kinda needs to be there
As for the future of Torchwood, I thought RTD said it was on indefinate hiatus due to "personal reasons"? Granted that could mean they can get the funds to do season 5 properly.