I would like to see a button with similiar functionality to what I saw done on humble bundle years ago.
Ability to influence the share that the platform gets.
Itch has this revenue sharing where the publisher can set the ratio. But what about the users? We do not even see, how much share the publisher set. So we do not see, if it is a generous dev or a cheapskate.
So, there could be a button like, add extra tip for Itch, along with the buttons under "Support the developer by paying above the minimum price". So when overpaying, you could make sure that the revenue share would inlcude at least your extra tip.