I was wondering the exact same thing!
My savegames exploded together with the rest of my last computer, so I'm trying to re-do some of them right now, and after only seeing the previews, ME1 feels so damn old. It's almost no fun anymore. (But I sure will feel the difference next week I guess!

)
Bioware should make some kind of savegame-generator for ME1. Just kind of a little checklist-program that generates custom savegames with (at least most of) the things that carry over. I might even buy that as DLC
I mean think of it... It'll be like hell if you really want to see everything in these games - and lose a full set of ME2-savegames. You'd have to play through both games multiple times to make new ones.