Mithol
Potential
These parts of your note, I disagree strongly with. When Buffy announced her plan at the end of the season, and Giles said it was "bloody brilliant ... if you want my opinion," and Buffy said, "Really do," the look they exchange lasts an extra beat, with a meaningful smile from both of them. It's not as definitive as I would have liked, but to me it's unquestionably a reconciliation. They were fine at that point. The depth of their feelings for each other over the years finally won out. They did reconcile.
Well, that wasn't good enough for me. I'm glad they were okay with each other. But like you just pointed out, it was barely more than a moment. And I think that relationship deserved more. I mean, come on, the amount of time they spent on Buffy's relationship with Spike in those last few episodes. And all Giles gets is a look.