I'm trying to get members of my old Go club interested in the Game of Go proposal on Area 51 and one of the first questions that came up was whether or not it would support posting board positions. I mentioned that there was built-in imgur.com support, but everyone agreed that a built-in board editor would be much more preferable. It wouldn't be necessary to actually play a game with someone over the site. Just an editor where you can set up a board position and play through different lines by yourself prior to posting would be plenty of functionality for asking/answering Go questions. (Something like GoWiki could be used to store the position as text, but present the diagram as an image.)
Math notation support was already added to the Mathematics site and that was extremely well-received. I can see customizations being useful for the Chess and Board and Card Games proposals as well. Are any other customizations specific to a given site being planned?
(Also, is there a better way to suggest customizations for a site than posting here on Meta? Is there some way in Area 51 to share these suggestions on a site proposal itself?)