My local camera store, Gordon's Photo Service, is celebrating it's 26th anniversary today. Gordon is bringing in various sales reps during the celebration. Today there was a rep from Ricoh at the store. He had the K-50, the K-S2, the GR... and a working prototype of the K-3 II!
I play around with the Pixel Shift function and talked to the rep about it. Yes, you absolutely need to use a tripod for this feature. Don't fool yourself by thinking you can hold your breath and brace yourself against a wall. You'll get a strange halo effect if the camera or your subject matter isn't perfectly still. The in-camera processing is fast enough for a landscape shooter. This feature doesn't suit my style of photography so it's kind of useless to me. I won't be upgrading to the newer model.
Oh, and don't hold your breath hoping the pixel shift feature will come to older camera models. It won't.
However, you can hold your breath for 5-axis SR coming to Ricoh soon.