Mike,
First, the price for the WK8000 is $499, not $399. The retail price is $649 and Casio doesn't allow stores to post prices less then their MAP price which is $499. If you really saw it for $399, GC made a huge mistake and would actually be loosing money on this product. The mark up on these inexpensive keyboards is really small. Also, at this price point there is no competition for an 88 key digital keyboard with all the features. Did you try the drawbar organs? Did you try using the modulation button to add realistic leslie simulations. Also, if you edit the stock piano and take away some of the digital reverb present in the stock piano and store it in a user voice, you would have heard a very good quality piano. I agree with the 32 note polyphony, but even the Yamaha YPG 525 which sells for $629.00 and has the same kind of action and features only has 32 note polyphony.
As I state often here, if you tried the keyboard at GC and didn't get a knowledgeble sales person, you probably didn't get to hear the Casio at it's best. My only disappointment with Casio is it's ride and crash cymbals. These are not up to todays standards.
I can't argue with your opinion of the feel of the keys because at this price point, you can't expect too much. But I do think that for it's price, it's a lot of keyboard.
Again, I get to play around with these boards everyday of the week so I have the advantage of knowing the in's and out's and can tweak things you might not of had time or the knowledge to try out at GC.