As the title says, I am proposing this idea motivated by a negative experience that just happened to me (unhappy reviewers who don't care/don't understand my question).
I believe reviewers should be allowed to choose what to review and what NOT to review, without having to look at each one of the posts pending review before deciding whether to review it (they have already started the review). It appears that no such feature is available now.
The more advanced math gets, the more intricate the specializations. I can only name a few generalists: Gauss, von Neumann, and Tao. That's all. I am pretty sure no reviewer here qualifies as a generalist and cares about and understands every question they review.
When I go through the questions, there are many that I don't understand or don't care about at all. If I had to look at every one of them, it would be torture.
It's reasonable to believe that the posts requiring review are a fair sample in terms of topic coverage. So I can imagine what the reviewers have to go through.
Of course, this feature wouldn't work for people who stubbornly choose to do what they don't enjoy doing. But I am sure they are in the minority here.