Initially I had the idea for something more faction oriented, but did ultimately abandon it because it was too complex and there were also LIs added later on that were from other factions. (Reuben, Quill, and Lance are all unaligned with the two main factions).
Ultimately the relationship metres in this game just exist because signposting to players what effect their choices are having is always difficult in a visual novel absent some kind of visual. So they ultimately became a "Did the LI like that choice" sort of indicator. LoL! OwO