I'm not trying to strawman you, it's just that I thought I wouldn't have to write five lines of explanation for what I wanted to say, but here goes.
You want that AI escort their settlers, because you - and some other players - make a habit out of declaring war on them to snatch up those settlers. At the same time, however, most human players do not escort their settlers either, fully counting on the AI not declaring war on them just to snatch the settlers away. If you want the AI to escort their settlers, that means - directly - that you want the AI to see other players at peacetime as a danger to their settlers - in other words, you want the AI to consider declaring war to snatch settlers a thing. And that means an AI that is not roleplaying, but gamey. And, as I mentioned a while back, most players aren't going to like an AI that plays that way - AI is, according to most people, supposed to role play. From what I've heard on this forum, the AI in Civ V was originally programmed to play more like a human, and people hated it because they felt it broke immersion.