Interesting question. In some ways, if you include Detta and Odetta she went through the most changes. After she became Susannah though, in some ways I guess she went through the least. (Well, unless you count Mia, but
Spoiler:
she was an intruder
.)

That's not to say she didn't change, but I think it was a bit more subtle than Jake and Eddie's. I'm not sure we can discount what happened with the previous personalities or even Mia though. It's all part and parcel of what made her who she is.