With CAPsMAN, there is no way to monitor interface load and retries (CCQ) at present.
I propose submitting a v7 feature request to add /caps-man interface 'packets' and 'retries' fields, cumulative since interface-up. The same data could give a 10 second CCQ retry percentage.
This would allow monitoring radio cell RF qualty and load over time, which is crucial to detecting suboptimal channel or radio behaviour in larger networks.
Comments/+1s/suggestions, or no-one else feels it is has value in larger networks?