This is interesting...I don't want to ask too much of you right off the bat, especially since you are new to coding and stuff, but...
I think it'd be nice to include the server number in the GUI. I'm sometimes mid game and a teammate wants to watch me in it, but I need to stop moving to type /info to check it, so it's not good mid-combat, which is sometimes what they wanted to see.
Number of tributes left/timeleft until refill/deathmatch also sound like cool ideas.
You know what I just thought of? Something for the far, far future, but...what if you had a little map option, only accessible outside of the game, that allowed you to see an overhead, minimap like view of all the different maps? Then, allow a community portion to it where they are able to "draw" their chest route on it with a description/instructions and publish it, so that some chest routes can be known/become popular? I think that'd be awesome!
(I know something like this likely wouldn't happen for a long time though, if ever. Just a little idea that came to mind...)
Oh, and another thing; (not sure how easy this is to do, probably not at all.) what if you had a little ding noise happen, or possibly have something appear on the in game GUI, that tells you when a highly ranked player is online in the server you are in?
I could keep suggesting things for it all day, but I guess I'll stop here for now...