A possible compromise idea: I still select and assign ops, but your level of recent RinkChat participation determines your op priority. The most active ops get the highest priority. Then, if an active op stops being so active, the priority gradually drops, and maybe if it goes below a certain (low) threshold, the ophood disappears entirely until the level of participation comes back up.

I'm not convinced that solves all the issues I wanted to, but I think solves some of them while circumventing the concerns I'm hearing here.