I would never replace Cherish. It's such an important song in her discography in my opinion. She's quite smart to include it too because some casual fans like it more.
I think Dress You Up in the remix/edit form or Causing A Commotion single version would've been ideal to add; the latter considering she'd just performed it for a year
Personally I've always found Who's That Girl not as good as Causing A Commotion but it did sell well. A Q-sound mix incorporating the 12" mix would've been cool when I think about it.
But I would still keep all 17 tracks as they are, only add one.