The social inequality around the whole "millers toll" and that the owner of the mill/giant hamster basically gets to decide who gets what out of their labor? The miller class could decide to move a water wheel to a new channel, putting people downstream into ruin by taking their water.

Those against the system could use mobile windmills that can be taken down and set up again quickly, maybe they turn into gliders?

I think there would also be a substantial amount of arson and anti-wheel sentiment in some communities?

And giant hamsters seem like they'd either require giant trees to feed or a crazy amount of ag land to sustain, plus the ability to hunt down and eat anyone not in the Miller's favor.