I would think smaller sensors have the advantage. The weak link should be the strength of the equipment moving the sensors. Therefore there would be less elastic distortion of the parts, less lag, less battery drain for a smaller mass sensor.
I would think so too, due the physical scaling laws that allow a hummingbird to flap its wings 60 times per second, and change its direction of motion far faster than a large bird can: the forces required to keep a larger sensor in place go up with the cube or fourth power of linear size, but the ability to deliver force often goes up only with cross-sectional area, so the square of linear size. But similar scaling issues rise with lens-based stabilization too, where the lens elements to be moved can be smaller and lighter in a smaller format, and require smaller movements on the same time scale. So it not clear that the advantage shifts between lens IS and sensor IS as format size changes.
I would choose my gear on the basis of actual testing and reviews, not this vague theory; rather than "prejudging" like this:
I would go for sensor stabilization on APS-C, 4/3ds and optical stabilization on FF.
I would ask what actual testing shows, for example in comparisons between the different sensor sizes where Sony uses sensor-based stabilization, in its SLRs with APS-C and 35mm format sensors.