Moderators have very little tooling to help deal with consistently bad reviewers. We have [review audits & bans][1] and some fancy stats pages. This is enough to stop true robo-reviewers, people that apply the same action to everything indiscriminately, but it breaks down when it comes to stopping just plain bad reviewers. I'm defining "bad" as reviewers who are otherwise paying attention (they pass all/most audits) but consistently apply wrong actions to things they review, actions they have to be corrected later. I've seen users that tend to "no action needed" most things, even if they are badly in need of an edit, comment, etc and other users who tend to "close & delete" everything, even if it's on-topic or otherwise acceptable. This is where it gets hairy.
I can look at a reviewer's stats and say "wow, 75% of this person's reviews are (no action needed/delete/close/etc) but moderators have no tooling to actually tell if this is pure coincidence or if bad actions are actually being taken, and no too