I want to start by saying that I love Itch. It gets so much right and is a fantastic place for indie developers.
The biggest issue that I would love to see resolved is for potential buyers to have quick and easy access to game ratings and reviews. At the moment you have to rather hunt for the ratings (on the game pages themselves) and the reviews are, AFAIK, only visible to the game authors. I'm at the stage where I will try to encourage people to leave a comment rather than a review as they are far more visible.
Anyway I still love Itch, but if that could be cleared up I would love it even more. :-)