About the worst criticism I've heard is around policies involving refunds (very short but charming games can be played quickly and then refunded) and shitware games clogging up search results (often Unity/Unreal Engine skeleton games with a new logo slapped on).

The first one discourages a subset of indy games, but ones that should be taken seriously.

The second, I think, is more of a problem for reviewers hunting for hidden gems than the public at large. Steam decided long ago to lean into Sturgeon's Law of letting almost everything go through and let the good stuff rise to the top. The other way to go is a curated list where you've already cleared out the garbage, but with the understanding that some hidden gems might be caught, too. If you go for letting through everything, then you should have mechanisms for highlighting quality. Steam is pretty good at that overall, but I see how it could be a problem for reviewers. After all, they're exactly the people who need to be trolling the depths and finding those hidden gems.

I don't think most people even notice those skeleton games all over Steam. I would never have seen them if not for J Steph Sterling pointing them out.

Suffice it to say that if these are the biggest problems, they're doing pretty well.