All of those matchups (save for the 5 newest characters) were discussed by Allan Paris and myself, and unless he's changed his mind on some of them, we agree with most of what's there.
Pai's not a bad character. You have to work hard with her to win, but that doesn't put her at an overall disadvantage with the cast. She has the speed and crushing to deal with most of the cast, in addition to a few other pluses here and there.
Again, she can be difficult to win with, and the person using her has to make quite a few correct guesses, but overall, she's still pretty good.
I don't agree with the Mila/Rig/Ein/Christie MUs, though.