Originally posted by Kunzite Of course it is. The current SR is capable of 5-axis corrections, up to 5 stops - and neat tricks like Pixel Shift and AA filter simulator.
OTOH, I could sometimes get 1/2" with the old K20D...
It's not a major change in hardware between 3-axis and 5-axis. The 3-axis SR in K3II was rated 4.5 stops. The biggest gain is probably in motion sensors that has gotten faster and with higher resolution in motion capturing.
It does not matter much as long as the rating is according to CIPA standard, which only test pitch and yaw (2-axis). The only thing 5-axis add is ability compensate better for high magnification shots, the other things you mention was already done with 3-axis.
To be able to use SR on GR, Ricoh need to design a new much more compact SR. Then it may be possible to only double the size of GR and add 50-100g on weight on GR.
If only wanting things like pixel shift and AA simulator, a much simpler and compact design could be used, which would offer better performance on pixel shift and AA simulator.
The SR mechanism is kind of slow for these things.