I don't find any launchbox.xml, but there is a XML by platform. @SentaiBrad are you sure this has been requested previously ? I don't find any bitbucket issue for this.
We can mark a game as broken but with lots of games it's difficult to search those which are broken for trying to repair them (change emulator, get another version of the game, etc..).
We just need a filter "Status" with 2 possible choices "broken/works"