Something else that might help, especially if we start banning all the better-known games, would be to give everybody a cheat sheet that they can pick games from for nominations. People can only nominate what they know, so popular stuff gets nominated over and over.
I'm thinking like a Google sheet that lists all 3,000-odd arcade games (no clones), with the genre (which can be pulled from category.ini for MAME), and the year of release, and people can browse through that for ideas.
In fact, I volunteer for list duty (I've got me some kick-ass game lists), but I guess that will be for next time.