Don't think 24mp APS-C will offer anything more other than slower PP times
The K5 is already a very good camera.
If Pentax can work on the problems of the overall system, that would be much better :
1. Better AF (esp. AF-C)
2. Better MF focus confirm
3. Better PTTL and better wireless commander (radio control??)
4. More lenses (esp. primes)
5. Tweakable HDR mode
6. Focus stacking
7. AF in video
IMO, things like better ISO and DR can wait a year or two as its really nice enough atm. Anyway, its more dependent on what the sensor seller can come up with, so its a level playing field (esp. between Nikon, Sony, Pentax)