And onto a plot twist of my own! Plot of the thread, anyway.
Beware, beware. There may be some ME2 character spoilers. Not many, but eh.
I was chatting wth a friend about what to expect for characters in ME3. We considered that BioWare needn't bring back any characters from ME1. Kaidan/Ashley can be wrapped up in a way similar to Liara in Lair of the Shadow Broker, with DLC. So could Wrex, conceivably. Furthermore, there wouldn't be a lot of sense in any of them coming back, considering they're all too important for Shepard in ME2. Basically, it's too much of a stretch to go from "We're totally not joining you" to "We're totally joining you."
So we considered the team as of ME2. Assuming a full party with loyalty and all surviving, we figured that eight of the twelve would likely stay on. Regardless of how the player ends ME2, Miranda and Jacob stay on with Shepard. It makes sense that Tali (now vas Normandy) and Garrus would stick around. Thane and Jack are potential love interests, so figure them to be game for sticking around (not to mention, there's no point to them going elsewhere, though they easily could). Grunt should stick around, since he considers Shepard his battlemaster. And then there's Legion.
We figured Zaeed, Kasumi, Samara, and Mordin would leave or be dismissed. Zaeed and Kasumi are DLC characters, one, so there's nothing to make me assured they would be brought back. Furthermore, both are essentially mercenaries hired as part of the specific mission, with nothing to suggest they would stay on beyond that. Too bad, but alas. Samara is in a similar vein, though not a mercenary. Mordin was brought on for a specific purpose, and unless there's a big science necessity in ME3, he isn't needed. Plus, he's old, and he probably has more important **** to do.
Anyway, that's what we figured. It allows them to keep an established cast in part, while still introducing some new characters. I have a hard time imagining them tossing out the entire cast, given how much time they spent building them up throughout ME2.
This doesn't take into account variables like incomplete crews in ME2 (for whatever reason) or non-loyal squadmates, but I'd prefer not to speculate on that.
What's everyone think?