If the omnichains work then we should be able to get some great responsive movement for pitch and roll quite easily, but what about yaw?
Yaw is possibly a movement that we can drop and the user wouldn’t notice, since the sphere is tethered we’re not able to spin it very much anyway, although this could change if we ever go wireless.
Even without motors to rotate the sphere we would probably pick up some rotation anyway, so at the very least it would be a good idea to have a small motor with an mecanum wheel to keep this rotation under control. Again, better Yaw movement can be part of the ‘optional extras’ package to keep costs down. If some wants to pay for it why stop them, but if its not necessary it shouldn’t come as standard. A group of four motors in between the belts can also serve a double duty to help add some torque to pitch and roll when the sphere is lined up correctly.
I suspect that it would be a better use of peoples money to spend it on a heave function before yaw, since that is so much more easily felt, then we can have a 3.1 DOF platform or 4 DOF if the user wants to spend the money.