Indeed this first offering from Ricoh-Pentax seems a bit odd... On one side, Pentax has wondeful pancake lenses, so they are "mature" enough to make the most out of a mirrorless system. On the other hand, in order to use these lenses, and to keep a big APS-C sensor, they could not shrink the camera by that much.
So... for those with a K5 and a few pancakes, I think the attractiveness of the new camera will be minial; since a K5 with pancakes is already quite small. Seems the target will be people looking at entry level DSLRs?
It will be interesting to see when Ricoh will come up with a GXR module for a K mount.