your implementation is not a good idea. you mod overwrites any movement bonus.
concerns: RPG, RPG System, Quality of Life research and certainly a few others.
If you have no other solution than modifying character_running_speed_modifier, then you should at least include a warning in your description.
Furthermore, the character remains slow when the mod is uninstalled.

"character remains when the mod is uninstalled" is an understatement, my save is broken and now I'm stuck at a snail's pace

@Professor_Farrel
install an other mod to modify the speed.
- with Creative Mod you can set any value (and many other for cheating) ;-)
- or if want dynamically run faster/slower look at my mods Kuxynator's Running Mod / Kuxynator's Running Mod (cheat mode)