I forgot to put my preferences in earlier...
My Dirty Dozen:
1. Liara: I just hope they revamp the Adept class. Actually, I hope they do away with the whole "powers don't work until all shields/armor/barriers are down". That really killed the fun of playing an adept. Once you get their defenses down, the enemy is pretty much dead anyway.
2. Kasumi: With on ship conversation this time. Her Shadow Strike is very useful and she could be a cool character.
3. Kal'Reegar: Why? He's voiced by Adam Baldwin (I'm a Chuck fan), he could provide that loyal soldier type that they tried with Jacob but wouldn't be boring, he could give us more than one squad member of the same species so we can get some inter-cultural dynamics, and he was great on Haestrom.
4. Tali: I like Quarians.
5. Wrex: I felt a kinship with him, unlike Grunt (who bored me with his one-dimensionality).
6. Mordin: Everyone loves Mordin, right?
7. Miranda or Jacob: One or the other, because I'd like to have a Cerberus connection to help provide insight into the Illusive Man's dealings. I'd prefer Miranda, but I don't hate Jacob. He just needs more depth and a different skill set.
8. Anderson: He's not too old for this shit. He puts up some good fights in the books. I at least want him on board the ship.
9. Thane: He's a unique type of character compared to the rest of the cast. I like different perspectives
10. Legion: A Geth squad member is too intriguing to pass up.
11. Ashley/Kaiden: My main Shepard didn't romance either, but there are still loose ends that need to be tied up. But they should not be swaps of each other. It was understandable in Mass Effect 2, but they are different characters and should be treated as such if they are going to be a full squad member.
12. Aria: It's speculated that she and Wrex have a history. I have a feeling she can hold her own in a fight, as well.
People I left off:
-Garrus: My Shepard has a kinship with him, for sure. But I want Garrus to be a leader of his own in the game. We spent all of Mass Effect 2 helping him deal with the things that went wrong when he first tried to be a leader. The Shadow Broker files say he has leadership skills that are being squandered while under Shepard's command. I'd like to see him with his own team (and maybe have a moment like in Shaun of the dead, when the two "teams" in it cross paths") and I'd like to have a joint-operation with him.
-Samara: Most of all, I feel she should be done with Shepard. Her duty is finished, she should have other business. Other than that, she could be dead from her loyalty mission.
-Grunt: I didn't like his character. It was too one-note.
-Jack: I would actually still like to have her on the team, just not more than any of the ones I listed. She showed some signs of maturing and seemed to understand what is at stake. I could go either way with her, though.
-Zaeed: I guess he's similar to Grunt, but that's not totally fair (I did say I want Kasumi for the next game, after all). I don't see why he would stick around.