I've tried to work a bit on a systematic diacritical system (on an expanded latin base) and I think Georgian could be made to work that way - what you need to do is:
- declare ejective series as the basic one and mark aspirated stops (aspiration is stronger than glottalization tbh, and it reflects in loanwords) - I mark aspiration with an interpunct ·
- use my dedicated set of sibilant letters based on West Slavic systems - s /s/ z /z/ c /ts/ ʒ /dz/, with carons on post-alveolars: š /ʃ/ ž /ʒ/ č /tʃ/ ǯ /dʒ/
- the single uvular which requires extra attention can again be marked with a caron (I use caron to mark "backed" pronunciation essentially): ǩ /q/
- velar fricatives I write as in IPA, with what's essentially greek chi and gamma: x /x/ ɣ /ɣ/ (note: I write Γ for capital gamma)
vowels are straightforward and don't require extra attention
the most complex letter in this system would be č· /tʃʰ/ which gets both the diacritics, dialectally you can also encounter ǩ· /qʰ/ tho (which is merged into /x/ in standard georgian)