All the tools I see around demand admin rights. But why?
At a guess, probably because the software is being installed (an activity often limited to administrators).
On the other hand, certain software like AutoHotkey has a zipped version which includes standalone executables that shouldn't require installation or administrative privileges (as far as I am aware). Of course, AutoHotkey isn't really a GUI program per se, as it runs text files you create, but it is generally fairly simple to do basic key swapping with.