I was really choked when the K-70 had come out. Only because I had just purchased a K-S2 a handful of months earlier.
They are both 'entry-level' cameras, but the K-70 actually has a big step up from the K-S2:
PixelShift II
4 more MP
14-bit RAW
Noise reduction accelerator unit
Extra stop of shake reduction
'hybrid' AF in live view and video
better buttons and grip
I was still really glad for the K-S2 and learned SO much about photography from that very capable camera... but the K-70 is just a wee bit better and it made me totes jelly.
Anyway, after my K-S2 died after some 50,000 shutter actuations, I wasted no time picking up a K-70 for myself