IMO Pentax should keep the current two models and add an improved SLR to the lineup, such as the K150D or K200D. Based on their previous poor marketing decisions, though, I doubt the future DSLR lineup will snap of out their habit of releasing two similar bodies (one being a stripped-down version). Here are a few examples:
K100D vs. K110D
*ist DS2 vs. *ist DL2
SuperProgram vs. ProgramPlus
ME vs. MG & MV
The K100D/K110D are already about as small as DSLRs get, so why make one of them even smaller by the removing the top LCD? That would lower its status as an SLR even more! Also, I personally think that using pentamirrors is a joke, so they'd better stop!
As for resolution improvements, I think bumping up the 6MP's up to 8MP would make them more popular.
A full-frame pro DSLR would also be nice, but I know it'll never happen:
If any of you have the *ist D, have a look at the mirror. You'll notice that it's a full-frame mirror as opposed to the small one fit onto all the other Pentax DSLRs. This suggests that Pentax originally considered producing an FF camera, but not any more 