I know this can't really be done with 3rd party games, but for Stardock games currently launching through RTP just brings you to the main menu. Take Demigod for example, it'd be great if when clicking "Launch" from the RTP game invite chat it'd throw everyone in that chat into the game lobby itself.

As it stands now, using RTP to launch a game of Demigod isn't really any easier than using IRC or an IM service. It helps you find people, but you still have to give everyone a game name, password, etc and then they have to individually find the custom game and join it. If RTP could be integrated enough that it can launch the game and go straight into a lobby, that'd save a lot of hassle and make it much more attractive to use as well.