Thinking extremes, you probably wouldn't want a solid hoop- say, steel for instance- because unlike trains, we need some conformity with the road to get an acceptable level of traction. So maybe we add a layer of rubber to the hoop where it meets the road. Gained some conformity for traction, also gained a bit of resiliance for bump absorption. Some r.r., yes, but what else are ya gonna do?
Take all the resiliance out of the wheel and stick the suspension with all that monkey motion, and you will have one busy suspension!
It will be like adding a bunch of unsprung weight, even though it is partially sprung. It'll likely be too heavy to respond to higher frequency excitation- maybe big ol mushy suspension pivots can handle that.
Wonder what r.r. the Tweel has.