Well, this is a "quantity" approach to the problem, that does not take into account the "quality" of sounds. I have tried the Motif and, even if Yamaha says that it sports some of the cool voices of the pro, I still think that the 9000 pro sounds better. Unless you are into techno, hip hop and stuff like that, the 9000 pro offers you a much better choice of solo voices to play with. Acoustic and electric pianos, organs, guitars, woodwinds, accordeons, brass, strings, you name it. Plus, I think that the Motif has a "cold" quality in its sound, that reminded me of my old Yamaha SY 99; I don't know how to explain it, but I definitely could not define its sound as "warm".
Going back to the 9000 pro, I think that its biggest limitation, as an arranger keyboard, is the quality of the styles, but it is true that you can buy commercial styles (the good ones are pretty expensive, though).