Probably whatever people get out of buying a 21mp canon or 24mp nikon or sony. Pentax is not a company that makes their name on sports photography. They typically push their camera's suitability to outdoor pursuits in their advertisements.
At least that's what I would hope for. It seems sensible. Lanscape shooters who aren't too invested in a system already would find it very tempting. I'd want one, but not be able to afford it. Tripods and base ISO are the way myself and many others work.
What [as far as I know and what happened to me] Pentax customers are usually craving after are lenses, lenses and lenses. For the sheer quantity of them. And obviously, the quality of the glass.
Which, for instance, makes people buy at the very same time the FA43 1.9 and the FA50 1.4/1.7.
The ultimate quality of the Pentax bodies has been, so far, their ability to be just a tool, with zillions options [for heavenīs sake, they had variable AND bracketable ISO from the very begining]. The Pentax bodies are kind of servants of their owner. Sort of "just right" theory.
All in all I am very doubtful about what might happen with the über-Pentax. One one hand, it seems that that über-model will be aplicable for a maximum of 3fps style of shoot [fashion photography, studio photo, macro, landscape, architecture]. For that:
If they get to FF, they will have to compete with the marketing resources of Sony. But they have the new player behind [Samsung], eager to set themselves as the Korean Sony.
On the other hand, the do have everything set for a 645 digital. And they are leaving probalby the best ever made lens system orphan [the 645 system, sorry, Hassy shooters]. The 645N and 645NII were pretty ubiquos cameras. It would have been a very sensible upgrade path.
All in all, thatīs the problem I see with Pentax. Their Pro series were the MF cameras, not the 35mm on steroids. They have now two paths. Which one will follow?