Well said WDMcM!!

Manufacturers would probably not want to market an arranger that would work best for your traditional arranger player and the hip-hop musician. Neither of them want to be associated with each other.

With respect to “As for the current arrangers not being up to the task of some of today's music, well that's just not true. It is true if you plan on just using the factory supplied styles and sounds. But if you learn how to create your own styles and edit your own sounds, most any of the mid to high end arrangers would fit the bill.”
You’ve hit the nail on the head. Your traditional arranger players do not have the skill nor do they have the interest in creating their own styles and sounds (which is the linchpin of hip-hop and modern music).

And, there does not seem to be overwhelming evidence that there is a modern music market for arrangers. The question is not just whether traditional arranger players are interested in playing hip-hop. But it is whether Hip-hop players would use a traditional arranger.

For hip-hop and other modern music manipulation of audio is critical. Whether you agree with it or not, that is where music production is going. Why do you think almost all the hip-hop people use an MPC? The only companies that seem to be trying to bridge the gap are Ketron with the Audya, Korg with the PA2x pro and the Mediastation.

And I still say to any one, find a song in the Hip-hop or R&B style and try to play it on the T3 or G70 in arranger mode and first see if you can get it to sound authentic and two see if your approach is different from when you play days of wine and roses.