I have noticed a handful of creators that make it into the "New & Popular" tab pretty consistently that use AI-generated art assets. I already know that I am never going to click through to view their game, so it would be nice to have a way to declutter my feed. 

Alternatively, being able to hide a specific project would be useful since I'm not very likely to be searching for a game I've already completed or a project I've already downloaded.

That would be nice features indeed.

In the meantime, I made a tool for that if you can run browser extensions. It's a script for tampermonkey that lets you hide projects individually and by developer.

For ai assets specifically, you should be able to use the no-ai filter for assets https://itch.io/game-assets/tag-no-ai . Older assets that did not fill out the ai disclosure question are supposed to be delisted, but there was no date mentioned when this will happen.