I mean there are modified gravity candidates other than MOND. I think those are worth more consideration. MOND seems pretty well disproven at this point, yet somehow it's still what people focus on in terms of modified gravity! Where are the tests of other modified gravity theories?

Indeed, in terms of the negatives of MOND, I'll go further than you -- MOND barely explains galaxy rotation curves at all. When you look at the actual rotation curves compared to MOND's predictions, well, yes MOND does better than Newton w/o dark matter, but it's still pretty heavily fudged. If you have to fudge it that much, it seems to me there's no point. So I'd say that really MOND doesn't explain any of the three.