Since the group is so large and seemingly balanced, you should either:
(1) Put your enjoyment first. Play whatever you most want to play, period. Or,
(2) Take the opportunity to try out one of the new "core" classes. IMO, e.g., the Warlock is too narrowly focused to fill in for a wizard in a small party, but in a party with a wizard (or two), you can explore the class and not feel like you're shirking your meta-game duty.
Jeff