One thing I'd really appreciate is better ways of filtering/searching game jams to find ones that are explicitly open to physical games/tabletop RPGs/LARPs.
First-class support for specifying a range for "number of players" and "length of game", and searching for such things, would be great.
Being able to easily sell physical books or physical versions of other materials and ship them myself would also be great and allow a lot of flexibility for things like board games.