I hear this complaint or should i say concern all to often.
I had issues with softness with the istD, but my K10D jpegs are just fine. Most cases i only need to sharpen the same as my D1 and D2H, about 80% radius 0.3.
I have my camera set at "zero" or factory settings if you like.
Bill Fourtney a Nikon rep i met up with last year, told me the best settings for cameras like the D2H and D200 are "zero'd" out. I have used this advise and i seldom have problems. I sell my photos so i need something nice, and these settings work, for me and my customers.
I have stopped reading web sites like dpreview, as all it takes is someone saying the jpgs are soft in the Pentax XXXX and every one panics. Most camera stores offer a refund or exchange in 10-14 days if your not satisfied. My suggestion is buy it, look at it, if not happy, return it.
The sky is not falling.
Dave
Dave