The real risk is the commercial one. Nikon sales and profit figures are just out - declining DSLR sales, declining profit and no end in sight.
At the moment the Pentax K3 is probably the premier APS-C DSLR on the market - features, usability etc.
FF as pointed out by the OP - there is a big Nikon line up, and also a good Canon line up competing, As the market contracts then these two big players are going to complete furiously to maintain market share. Nikon is more vulnerable as it is more focused on cameras than Canon - which has a much broader range of markets it competes in.
So, whilst Pentax/Ricoh continues to face calls for a FF camera, and the marketplace shows a steady trickle of users selling Pentax gear to move to FF - it seems pretty minor in the big scheme of things. Yes, having halo products is always good - but only if you execute them exceptionally well. If you execute poorly then it adds to problems. Nikons recent issues with the D800 and D600 have shown this.
Originally posted by rbefly Stick with what you do best. The premimum APS-C market is there for the taking. Pick your fights well.
I agree - Pentax has the opportunity to remain the leader in this segment, with an excellent lens line up (way better than Nikon), innovative product, and a WR system - with increasing lenses arriving. The competition here will be from the excellent Olympus OMD m4/3 models which are smaller, lighter, have really good lenses, and give up very little in terms of IQ.
If Pentax do decide to enter the FF market it will need to be in a very well defined niche - my guess - the smallest FF camera, using the K3 body, pro level outdoors / WR model and very ruggedised. To try and compete with Nikon and Canon head to head with general large DSLR would add nothing to the market, and would struggle to have have unique selling point.
We live in very interesting times, and in reality are spoilt for choice with camera systems and bodies