It just occurred to me that my "perfect" sorceror is probably screwed for ToB. If they introduce a couple useful new spells at low to mid levels, she won't be able to choose them.
I think it would be nice to rechoose your spells when importing a sorceror, but this might be too much work to implement for just one character class. I know we can create a new character with 2M exp, but it's not the same.
Even if they don't introduce new lower-level spells worth picking as a sorceror, some spells are probably going to be a lot more or less useful in ToB than in SoA, so I expect people are going to want to change their spell lists drastically.
Well since ToB also will introduce some ingame maps, and not just maps after the defeat of Irenicus, I'd start a new game, to get the full enjoyment of ToB. That is also the reason I haven't been playing BG1+BG2 for some time now