Why not create a framework similar to Nexus Mod Manager where you have a centralized location for managing all of the libraries, effects, game lists, and presets without having to create endless duplicates?
You can already do this. The setup tool is creating separate copies for simplicity, but nothing stops you from configuring ReShade to use a central location for effects instead (see effect and texture search path settings on the "Settings" page of the overlay).
I'd also like to see more options for making donations because we all know you're doing this out of love but not all of us subscribe to one method of making donations.
More options are not really feasible for tax reasons (it is near impossible to keep track of all possible countries for VAT manually).