I couldn't agree more - Lala and Ghoulia should be smaller (in my perfect doll-world she'd have an arched back, too), and Abbey should be bigger!! - They have the molds now.. but I guess it wasn't something they spend any thought on at the very beginning and now it's too late to change them. Very sad. :<
I've been thinking about that too.. It really is a shame, but they probably won't change any pre-existing characters now. Personally I wish the most that they would give Ghoulia a total overhaul including a zombily hunched back and a new face sculpt that looks more like her artwork; they completely lost the adorable awkward nerd look in the dolls.
Anyway, more on topic, I'm ok with the body shape of MH dolls - Mattel hired some wonderful sculptors - because they have so much life and expressiveness. Personally I don't care for the extreme arch in their backs, and I wish they were more realistically proportioned, but I don't care that they don't fit in Barbie clothes (I kinda hate most of Barbie's clothes, especially the ones that have "Barbie" all up in the fabric print, which is most of them). I do appreciate that there *are* other doll clothes and shoes out there that fit MH, but I'm not sad that one of them isn't Barbie.
I would give an arm or a leg to see a line of dolls that included some plump characters, but that will never happen, especially with Monster High.