Yup, I think we're kinda saying the same thing. I could definitely see, in the interval between 1 and 2 -- the two years shep spends dead -- the rest of the Normandy squad pressing their respective governments and having real tangible success -- Garrus, Liara, especially the council races, so that they begin to prepare council space for the reapers. Then Wrex on Tuchanka gets the krogan ready, and Tali gets the quarians ready -- or at least starts to, I could see Tali having a tough time with the quarians; they love to debate, and yeah she is the admiral's daughter, but she's also a kid just back from her pilgrimage.
In ME3 shep would still have to get the krogan to co-operate with everybody else in council space, etc etc.
It could've work... better than "oh let's just deny the reapers exist despite all shep's, and others', evidence and hope the problem just goes away."
Ah well, we got what we got.
Shameless plug for my story idea's time!
If I was in charge I think this is how I would distribute the ME1 characters:
Council - Begins building up fleets, renew the patrols outside the Perseus Veil, entering diplomatic discussions with different government in the Terminus Systems, talking with the Quarians about retaking the Veil.
Anderson/Udina - depending on the human representative and Council version, the Alliance will get different concessions in various treaties.
Shepard - Doing main plot stuff
Liara - Joins a Council expedition team to explore the Prothean ruins on Ilos. Possibly recovering her mental health.
Garrus - Depending on interactions during ME1, he's either promoted at C-Sec or running possible Spectre business on Omega.
Wrex - Largely the same as ME2, although additionally he starts researching Saren's genophage cure (not cloning).
Tali - Heads back to flotilla.
Ashley - At wherever the Alliance sends people to become officers. Williams curse is lifted.
Kaidan - Remains with the Normandy SR1 (Shepard is given a different ship as the Normandy's stealth capacities are used to scout out the Perseus Veil).