The problem with the Yamaha's is STILL that it is a closed audio environment. Unlike Ketron's, where with skill (or a good 3rd party supplier!) you CAN create your own drum audio backings, Yamaha's system is not only closed to only Yamaha provided content, but also completely impractical to use in a live situation - RAM is VERY limited, and loading in a different set takes time and a complete re-boot of the keyboard.
Until this is addressed, it is still a gimmick at best. Only a tiny fraction of the styles will be able to use the live drums, and the anemic ROM drum kits will be all that is left. Which, of course, begs the question... are you going to WANT to show them up for how naff they are by using the audio styles much?
You need to pressure Yamaha into opening this system up. Easy import of .Wav files into the style sections, and rapid loading of new audio styles.
Imagine, if you will... say you got BFD2, or the Superior Drums libraries. You could save each of your current Yamaha style's Drum Parts as MIDI. Then run these MIDI files through BFD2 and render .Wav files of each section (including the Intro/Endings). You would then be able to re-import the FAR better audio versions of these styles (tweaked to YOUR taste) into your arranger. Voila! ALL your styles, not just a tiny handful, would be radically improved.
You would also have the ability to mix in modern 'loop' or breakbeat audio onto these files (or if Yamaha would open up the usefulness of the Multi-Pad Audio feature to allow a .Wav loop instead of them being a one-shot as they currently are) and have the ultimate modern 'drums and a loop' sound at your fingertips. 3rd party style creators could do much of this work for you if you don't feel up to the task.
But all of this is a pipe-dream unless Yamaha open up the system to the user. And, unless considerable pressure is exerted on Yamaha, I simply don't see this happening. If you want this, it is up to YOU...
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An arranger is just a tool. What matters is what you build with it..!