Personally, I don't think the Roland W30 can ever match a very good Piano sound from the latest keyboards like the Yamaha XF or other brands. Nor can it really match some of the best software out there. I think using the W30 as a midi controller in that respect is a wise move, although I would probably get one of the newer controllers that have more features. My Roland A33 works well for an older controller simply because it has 73+ keys on it.
Furthermore, I have yet to really find a low enough latency solution that allows me to play the piano as expressively as I need to. No matter what I do, I always get lag in some way or another with computer software. I am a heavy piano player and I just can't seem to get past latency issues on Windows computers. I have yet to try an Apple Mac, so maybe that is better. Latency is the real killer for me with regards to software. If I did dance music, perhaps I would think different.
What interests me about the W30 is the Lo-Fi unique sound and filters it employs. I tend to play samples and sounds that cater to the strengths of the W30. Pianos and Real instruments are not the Roland W30's forte. It's great for some unique synthetic piano stuff, but I much prefer using the W30 to create sounds and play samples that are more synthpop, dance, RnB, HipHop, SFX, or Vocal oriented.
To me, the greatest thing about the Roland W30 is how easy it is to map different sounds across the keyboard. It's also very easy to load pitched samples across the keyboard. The Roland W30 is a "single layer" ( two is tricky ) piece of electronic mastery. It's pretty sweet and very powerful.
I may be old school, but physically jamming on a Keyboard Workstation is still the way to go. Indeed Software is the future perhaps.
Great topic.
Jim