As far as classes go, play what you'll enjoy. Not what we may need. I've always found that people will be more into a game/guild if they are having fun.
Playing something for need is great and appreciated. But I'd much rather have a guild full of Rangers that are having a blast with their class and game than a group that is playing what's necessary, not really enjoying it and looking for the next game because of it.
We can fill in what we need by recruitment after the fact.
TS is going to be a must however just due to the PvP environment. Think of it in the exact same terms as any FPS we play. Yes you can be a good team player without Voice, but it's SO much easier to say over TS "I'm getting ganked in White Sands!!" Than to have to type that out or even attempt to while in combat.