This seems to be a feature that is found in many first person games going back well over a decade - the ability to have “always run” on so we don’t always have to hold down the SHIFT key to run.
Honestly, it’s not too often that you see anyone travelling in Rust that isn’t running anyway. Having the option to have run on permanently and using the SHIFT key to walk instead would be nice. I know my left hand is cramping up from playing keyboard Twister to hold down the SHIFT key all the time. Seems to me this would be extremely easy to implements via a single check box in the F2 menu alongside the “reverse mouse” command.