I can't believe that's the only part of my post you chose to engage in.
Do you have a source for the claim that they're only 5-10% pit?
But - there are several sizes of American Bully - and I would bet that over time they will emerge as distinct breeds, if they're not banned first.
The pocket and micro bullies are small and so horrendously deformed that DFriend who works as a vet and does a lot of rescue centre work has had to put down several young ones in the last year alone, on welfare grounds, because they were in too much unresolvable pain. It's absolutely awful; she feels horrendous when she has to do it but there's no alternative. The Americans appear to have a new 'toadline bully' which is even more deformed than you're probably picturing right now.
The XL bullies are the largest of the lot, and are the ones implicated in so many deaths. My reference to the long legs was more about the foundation breeds than anything else but XL bullies have mid-long legs (compared to a SBT) and enormous girth.
The classic and standard American Bullies are somewhere inbetween the two in size. Inevitably if XL bullies are banned but not standard / classic they're going to have to find a way to differentiate between the two - presumably by weight. Probably most sensible just to ban the standard and classic too to avoid a wide raft of claims that "it's a classic bully not an XL he's just fat"
Personally I'd ban the lot, on temperament grounds for the big ones and welfare grounds for the little ones and links to organised crime for the lot of them