Alright, it appears that no one else has yet had a strong balk at the one-way aspect of the treaties. In hopes that at least one dev-type appreciates my quibble, I humble suggest that the UI text be changed from "X treaty" to "X Aid Agreement."
This would make the label of the active UI element more accurately reflect the effects of the choices on the Diplo-Trade page.
Yeah, it's definitely confusing at first, especially since every other game I can think of that has similar treaties
requires them to be mutual.
Once you understand how they actually work, they're not a bad idea, just confusingly named.
My first impression is that the AI sort of overvalues them early on, and undervalues them later (i.e., they'll trade their "aid" to you rather cheaply, and the other AIs don't seem to put any great emphasis on acquiring them from each other.) Another impression I have is that having these treaties, whether they're mutual or one-way, seems to give a sizable boost to diplomatic relations. In my first couple games, it seemed almost absurdly easy to form alliances with whoever I wanted to.