Again, based on ME2, it might be a lot of dialouge related stuff. But if I remember correctly, a lot of choices you made in ME that weren't fleshed out in ME2, are supposed to come to a head in ME3.Do "all choices" have any effect on anything gamewise, or is it just dialogue?
You would lose out on the Level/EXP bonuses you'd normally get from importing, which would allow you to start at Lv30, and is the only way to reach Lv60 besides doing a New Game+ in ME3. I'm sure there'll be some Morality Point bonuses as well.