I've noticed that a lot of suggestions or feature requests tend to get the response "requires a client mod." So why don't we make a client mod? Rather than making one for every add-on, a standardized library of functions available to the client that can be utilized by the server should placed in one add-on. On the client side, it will allow the server to use functions like resetting the FOV (apparently that requires a client command), transmitting requested settings, and creating new keybinds (perhaps 3 extra keybinds that can be bound to anything the user wants?). On the server side, it allows add-ons to utilize these functions or detect the extra keybinds, which seem to be kind of an issue. Also, it might add in support for 2D music, support for detecting keybinds other than the light key and via events, that kind of thing.
This would make a lot of add-ons possible without requiring several different client mods, and more functionality can always be added with Support_Updater.