I'm thinking it'd be cool if there were a way to compile a collection of scripts, images etc into a pack that tells Graal how to run. You'd be able to tell it not to make a game window and login a character, for example, and instead create a window based on your own specifications. Then Jagen's RC thingy could be a standalone window, being manipulated by Graal's inbuilt script engine. Further to that, one could make a chat client for any player to use - similar to a powerless RC, it logs into a server and pops up a chat room, also letting players PM one another.
Extend it a little and servers would be able to make their own Graal frontends, replacing the default menu. It'd only appear when the player uses that particular pack, of course, but those who only ever play one server could use it to replace their normal Graal shortcut.
Push it
even further and maybe you'd be able to tell Graal not to contact any servers at all? Instead of distributing levels to show off their creations, scripters and level makers could hand out these special compiled packs so that Graal can use them in a pseudo-offline mode (pseudo because the only difference would be that it never sends anything to the server - all the security stuff would be the same). Then they wouldn't need to bother making zips full of graphics etc.
Add more ideas of your own, then bug Stefan into implementing it