you should go over the character textures as well.
You should work up a list of weapons as see how you can make them work. You talked about discs and spears, but most of the heart of this game is the melee combat. I remeber tron (from the movies, never played the new games) and the only melee weapon was the light staffs that the guards carried.
(BTW not knocking your idea, a while back I did an online game -using the byond engine- based on an old tron game. It would be good to see something like this fully mature, but if you don't work out the concepts from the begining, you may hit a roadblock later on... Good luck with the mod and keep at it!)