Are these differences at the sample level, or is it just programming differences?
The latter would be a LOT easier to fix!
But this demonstrates how much inter-department rivalry exists between the workstation and arranger divisions. Just because they are part of the same company DOESN'T mean that one side is willing to give up it's 'best' sounds for the other side to use.
OTOH, maybe this is only fair, given how unwilling the workstation side has been to provide some of the more contemporary sounds and features for the arranger division!
It's just kind of sad that they can't get together and put a keyboard together with the best features of BOTH lines. Once Yamaha put chord recognition and complete style patterns into the Motif line, they should acknowledge that the arranger OS method of controlling those patterns is FAR superior to the simple, awkward 'function key ONLY' approach they use right now. Fills are a nightmare to cue up right now on a MotifXS....
It is about time that the majors dissolved the separate divisions for arrangers and workstations, and put EVERYONE, and all their good ideas, into one 'keyboard' division. Then, finally, we would get workstations that were simple to operate, and arrangers that weren't artificially hobbled into consumer playthings....
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An arranger is just a tool. What matters is what you build with it..!