The problem with the swivel LCD is that if you do make it bigger, you chew up real estate very quickly. Look at the back of the S5 - no buttons on the left side, only a few on the right, and the 4-way controller pushed right to the very edge of the body. I don't think a serious DSLR user would be satisfied with such an arrangement. Granted, a DSLR body is bigger, but I still think that you're inevitably going to lose too much room for the buttons you'll want.
As for your comments about the Pentaxes... Well, different strokes for different folks. Seriously - how often do you ever need faster than 3 fps continuous shooting or faster than 1/4000th shutter? (Assuming you're not a pro sports shooter.) IMHO, those are far more "on paper" things for the measurebators to fawn over than things that the average photographer really needs. The Nikon D80 that costs $150 more than the K10D does the same fps speed and fewer RAW (6 vs 9) or JPG (100 vs unlimited) files in a row and also tops out at 1/4000th second max shutter, but I don't hear those being brought up all the time as a deficiency of the camera.
For "big important" features, I think in-body image stabilization is a pretty huge one.
The "instantly change" ("Hyperprogram") is a very handy feature IMHO - basically, it means that you never need to spin the mode dial if you're going to stay in program, Av, or Sv mode. Leave it in program (with whichever line you've selected), and the instant you want to flip to Av or Sv, just spin the front or rear dial. On every other camera, you'll have to spin the mode dial (which probably means taking the camera away from your eye to look at the dial), then the appropriate front/rear dial, and spin it back when you're done (pressing the green button on the K10D returns to program mode) - that's one of those things that just makes it quicker and easier for the photographer. There's a bunch of such unique features, which is why the K10D got so much attention when announced, even in the C/N camps. Most are not earth-shaking but "gee, that's handy" kind of things. They had been asking photographers what they would like and they integrated many of the suggestions.
Does this mean that it's the best camera for everyone? Of course not. But that's why I believe that they made the choices that they did make, and hopefully it makes a little more sense to you after that.
There will be two new Pentax DSLRs later this year, at least one is almost guaranteed to be positioned above the K10D, and I'm going to guess that it's a safe bet that you'll get your faster shutter speed and fps with it, as well as most other features of the D200, for a bit less money than the Nikon. But that's just speculation at this point - the point is, the stuff you mention is stuff that is just not available on any sub-$1k camera. You can get a 30D with that fps and max shutter speed, for $300 more - that's 40% more expensive... and the D200 is more than twice the price. You have to keep price in perspective.