Hi
Go to http://purgatorycreek.com/ and click on the Digital Piano Shoot out, there you will find the dynamic range of East West Piano samples are as good if not better than the others.
The ones I have tried (True Pianos, NI, Pianissimo, Pianoteq) have worked pretty much spot on straight out the box, and with the quality samples that East West produce, I find it difficult to believe they would get their piano samples wrong.

Livestyler
Sounds like you were using a very early version which always was a pain in the backside, however it’s now much better, (V11) so have another look, and also make sure you have a look at the others I posted as well.

Integration
Try any of the computer based keyboards, and you will find you can select the Top sound samples as easily as the internal voices on your Yamaha. (This includes main and style sounds)
Regards

Bill