You could certainly define the filters as variables, but I believe it comes at some slight cost to performance. Saq has written quite extensively about good practice from a performance standpoint here, but the general recommendation is to avoid macro substitution when possible.
I do appreciate your effort to make your final product as user-friendly as possible! I’d like to gently suggest that it may be counterproductive to hide too much, though. If someone is interested in tweaking the display template, it’s likely that they’ve already gained some degree of familiarity with TW code, or if not, they’re at least considering dipping their toes in - and in this case, it can be more challenging to follow a structure across multiple macros and variable definitions than it would be to study it in situ.
As a personal example, while I have tremendous respect and appreciation for Mohammad’s wealth of out-of-the-box or otherwise beginner-friendly plugins, I found them very difficult to tweak as a low-intermediate user - mostly because he’s so very good at hiding his filters!