I have been thinking about this for a while, and I think it would be great to have the ability to:

• Read from /toribash/
  • Allowing Lua to io.open from anywhere in the toribash directory, but only for reading files would lead to great advances in scripts.
  • Perhaps even the ability to save in the /data/ directory, generate mods and shaders and such.
• List Files ( list_directory(dir) )
  • Allowing you to list all the files in a given directory (limited to /toribash or /data) would help achieve some of the ideas in my mind
• Measure Strings ( measure_string(text,font )
  • A function that returned the height and width of a string would allow for things such as custom chat boxes with emotes and such.
  • Also would allow for proper input boxes
• Server Side Script ( /runscript x.lua )
  • A command which would make the server run a script would make for great new gameplay elements.
• Kick, Ban and Say.
  • Unblock kick, ban and say from the run_cmd command.
  • Make certain scripts much better
  • Servers should have anti spam measures anyway (people can easily telnet and spam)...

I'll think of more later :P

I don't think listing the files in a directory is even part of the Lua language spec. Last I checked it was only possible via hacky tricks.

Dafe, it's not part of the spec the same way disk IO isn't an absolutely required part of the C runtime. While not included in toribash or the bare lua, there's a pretty typical luamodule, LuaFilesystem that accomplishes this. As normally implemented though, including it may not be such a good idea.