I try to never let this happen and intercept armies to fight on my own terms.
This is the way, enemies will try to stay inside your borders and only you can drive them away, either by paying them whatever tribute they ask for peace or by fighting, the last one is usually the best way to do this just get some nice charged mounted units and whatever units can counter theirs, skirmishers with special tradition are very nice for this but horsemen can easily take on damaged units too
Does anyone else have a common scenario of militaristic AIs declaring war early, targeting a city, realizing they can't capture it so they don't attack, and then they just sit around forever, never attacking and never willing to talk? In my current game I planted a city on the border with montezuma at a chokepoint and stuffed it with units, he obviously decced war cause monty. But his stack is almost entirely archers and scouts so he won't attack, but he's camped on a forrested hill across a river so I don't want to attack him. Now it's been 1000 years and he won't talk.
Now this is some weird stuff, 1000 years and he still refuses to talk?

Moctezuma is one tough MF. Have you tried to decimate the opposing force? that usually settles it, but after a few turns on a unsuccesful war campaign your enemies should be able to accept (albeit, they usually do by asking some money in exchange) if you want to avoid paying them for this you gotta fight and show them you are stronger, after this and a few turns they should be available for a free declaration of peace or even if you are strong enough you can ask them money too, but it takes time for the AI to process this, so it rarely is something you can do a turn or two after you beat them (usually it takes me like 5-10)
I have never been on this kind of case where a war has extended for so long because when someone attacks me I take it very seriously, being at war is not good for your citizens and can harm your development. Or at least that is what I believe
I'm not sure, but in such a long timelapse you should have been able to develop a technological advancement superior to whatever he has stationed there, just take that there and beat the hell out of him!
I think I remember telling a kind of similar story about two AI that were fighting, the attacker had a lot of skirmishers and archers while the defender had no sh!t on his city and yet he just stayed in front of it, not doing anything, about 400 years later they were still there just looking at each other... it was pretty awkward

sometimes the AI has a hard time doing sieges,
Future Tech seems to be wigging out, that straight line goes all the way back to Blister Steel. Anyone else have these two problems, or just me?
Yep this happens in my game too, had not noticed it because I had not looked that far in the tech tree
I didn't expect "Metalocalypse" to be the mod theme... (this shows up with both old and new terrain)
Yeah this can happen, only once for me though because of an improper installation of the mod.