24mm wants = this:
Nikon 24mm f/1.4
Big, big filter, $$$$$$$$$$$$$
Kind of silly for the DA series, but not FF. For APS-C the DA's 15mm and 21mm are perfect. Too fast and they get big an bulky and with WA the whole bokeh thing is less interesting and necessary.
People say they want wide and fast without really knowing what the major compromises are: very large, very expensive, lots of distortion, flare and hood issues (solved by the DA 15mm), etc.
If FF comes Pentax has a stellar but over-priced DA lens line-up. They should take the 15, 21, 35 Macro, 40, 50 (2.4) and 70mm, WR all of them and drop the production costs with plastic barrels and mounts, knocking 25% of list price. Same for a WR re-vamped 16-45, 18-55, 50-200, 55-300. 50-135 as well, and the 18-135 because, why not?
Keep a low-end K30ish entry-level, AA battery APS-C DSLR and we're done. Forget the whole Limited this for APS-C. Such a concept is price dead in the next 3-5 years.