I've got a L20 NT who gets picked up for team missions absolutely constantly, usually with all kinds of professions in the mix. Heck, I've been in a group where there were 4 doctors, 1 soldier and an agent, other than myself. It was hilarious fun, and not because of anything we were doing (missions targetted around 2x our levels). We were just having a great time dying repeatedly, mocking the mobs and being, in general, absolute hoodlums.
That being said, what's with all the hubbub I hear about people not being able to find groups to team up with? If you're a cool person who's able to deal with irreverence and a lot of sarcasm, I'll team with ya. I'm all about just having a good time, because as soon as the game become a second job to me, that's when I lose interest and go do something else.
I'd joing a guild, but most of the guilds I've seen are too 'serious'. I can RP, but I prefer not to most of the time, because sometimes that gets arduous and boring. I'd rather be out doing stuff, running missions, hunting, dancing on tables and going on newbie-buffing runs to all of the backyards in Omni-Ent. (always fun)
Anyhoo, my point is, why complain? Is it really that hard to find a good group to go hunting with, etc.? And those of you hosting groups, why be picky? Everyone's got SOMEthing to offer, even the lower-end levels. Now, oviously, there is a problem if someone is grey to you, but aside from that restriction, there should be no big deal in getting together a larger group. The max I've done team mission runs with was a team of 10, and we all loitered around the lobby area of a floor while someone pulled mobs to the 'killing ground'. :D Even the idle chatter was fun once everyone warmed up to each other. I have dozens of friends made this way...
Chill, people, play the game, intereact with people, and have fun! :)