A 35mm or 30 mm prime lens priced below $500. The current equivalent models are too expensive.
Nikon recently came out with the 35mm f1.8 at an affordable official price of $400, street price would be cheaper.
They realised the need of the APSC group, which the majority are, and the 50mm does not serve it's potrait lens purpose with its 75mm FOV equivalent.
And I know that, after using my fren's 50mm on his Canon, though Canon's has a even smaller sensor. And Canon has a 35mm prime below $500 too.
I hope Pentax would look towards a more affordable prime lenses.