Ragnarok Ekul wrote...
I think mass effect 3 will be set many years after 2, the reasons for this are:
certain plot choices such as curing the genophage and the quarians (possibly) taking back the homeworld would take many years of preparation and research respectively (also mordin states that the cure is still "many years" from completetion)
it could also write off characters such as mordin, thane and jack, as they all have illnesses or not long to live.
Not necessaryily true - the genophage cure doesnt have to be implemented - only seen to exist as a future possibility - that would be enough to unite the existing Krogan clans to fight under your banner for the future promise of a cure.
Likewise the Quarian / Geth issue isn't about retaking a homeworld - it's about saying (if you side with the Quarians against the Geth) 'After this is over we'll go wipe them all out', or (if you seek peace between them) 'Let's make peace and fight together now, and worry about living arrangements afterwards'.
On the issue of squadmates, I prefer to give BW the benefit of the doubt - I think Ash/Kaidan and Liara's cameos in ME2 were intentional for story purposes (and not just badly written as many people claim), to allow a greater role in ME3 - and furthermore that if they had had a greater role in ME2, it would have detracted from their future role. Liara's cameo seems to be setting up a greater interaction with the Shadowbroker, whilst Ash/Kaidan are die hard alliance soldiers - there's no logical reason as to why they'd have rejoined you in ME2, and instead I think their absence might be used to explain them rising in the ranks of Alliance heirarchy - Kaidan as a prominent Officer, Ash as Anderson's secret weapon perhaps.
Looking at the squadmates, I would guess that Liara, and/or Ashley/Kaidan will return as either squadmates or have significant NPC roles in ME3. If Wrex survived ME1 I'd imagine he will continue to act as an NPC leading the Krogan.
I think one of the main reasons Garrus and Tali were treated differently in ME2 is that there was fan demand to have them as new LIs. So whether or not they die at the end of ME2, I'd imagine BW will write proper parts for them in ME3 (on the basis they didn't die), and if you import a game in which they didn't survive, you simply won't see those storylines any further, and random Quarian NPC #1 will take Tali's role in determining the fate of the Quarian / Geth conflict.
Of the others, I'm not so sure