Well, the thread is not just about the possible fluff, I'll leave (as for the rest
) Steve decides what he thinks about it. It's also about the apparent deterministic value that triggers the passage to a certain treaty level. And also about diplomacy in general.
More specifically ...
1. You never know what THEY think of you, you only know what you think of them. In some situations it makes sense, but perhaps once you are in a treaty, an approximate estimation of what the other empire feels about you would be plausible and add a nice touch.
2. Once the threshold is crossed to get a treaty, perhaps it should be probabilistic, like 1% cumulative per month. Not certain as soon as the value is reached.
3. Perhaps a once-a-year reminder of how the relationship evolved with another empire would be also nice. How many points were gained or lost, or in a more RP-style, a vague message about a large or minor loss or gain of relationship would also be a nice touch.
Well, there are probably tons of other things that could be improved; these are just a few suggestions on top of my head, drawing from other 4x I play.