I already have my MacBook so that may be influencing me but there is my gripe. There is finally a separation between the MacBook and the MacBook Pro. There is an obvious reason for why the MacBook Pro costs more. Bringing them both to the same level creates the same problem Apple used to have... many (including myself) can easily justify getting MacBook instead of the MacBook Pro because the MacBook does everything you need the Pro version to do.
There are clear differences. Screen size and GPU are the big ones. If Apple introduced a 15" MB, then that would cause confusion.
Personally, I think the MB looks snazzier than the MBP.