Once you hear superior sounds, it is hard to relegate yourself to less. This, perhaps, has caused me to buy more gear than I should have.
I think of you as a consummate crafter of fine sounds, and that is meant to be a compliment. Whereas, I had a BK-9 and found the sounds and styles to be very good, I haven't been exposed to the quality you have, hence, my opinion.
There might be other audiophiles to agree with you, but not many would encounter this problem. I am glad,however, you resolved your problem.
Bernie
You are right that as a whole the BK-9 sounds very good. Piano plus strings solo without style is something I specifically need during weddings when accompanying soloists. I am surprised these problems occur with this way of using the BK-9, but I've sometimes had some dropouts when using very dense style arrangements, too. So polyphony is a certain problem, when using styles it only pops up occasionally, but that's the reason why Roland hasn't used SuperNatural sounds for style parts at all.
I just received the B-ware BK-7m again and tested it by playing the automatic intros and endings of two styles from the "Live Band" section. Sounds very good, even the guitar style parts sound good - actually regarding the styles alone there is no big difference to the BK-9.