[Kameron8]

I don't have an exhaustive list of things I think should or shouldn't be able to be dispelled, but one might argue you probably shouldn't spend 9 momentum to transform if you know you're facing someone with reliable dispels (with exception given to universally accessible Requinite, which, even if it's not reliable, I feel your pain on that one).

Shapeshifters, assuming they couldn't jack up their dodge high enough in time, at least have the ability to reinstall with an offensive attack via Chaotic Form. So even if their appendages won't be sticking around, they at least get to reinstall without any loss of momentum.