Voted PRE-A17. I prefer the old AI.
The old Ai felt more be unpredictable and more z-like. Though, i would like the new Ai on the future-planned Humans (then it makes sense for them to be super smart).
Currently the way Zombies navigate through puzzles like psychic labrats with an IQ of 10,000 means that people are just going to come up with (too easily) cheese builds, as seen in many Turret-Defence games where to win, there was only 1 min-max build where if you strayed from that design, you were only making everything worse for yourself or could be deemed a troll by other players. (Dungeon Defenders had this problem)
Zombies right now dig the land at random into a crater planet, even when you are on the surface.
When we had the old AI we would actually lose chunks of our walls and have breaches, resulting in some epic last stands. Now with the new AI...once you have your cheese-maze setup from a 'The Best build' youtube video (coming very soon i imagine, or already done), the original idea of the GAME seems to collapse into a Specificly choreographed dance of tasks to which you have to dance properly or die. I bet speed-runs would become a thing on 7D2D with how it is now.
Most things about your game are randomly generated and happen at random, but when your Ai becomes predictable, the core element of your game collapses. The only issue that remains with both sets of AI, is that there are not enough wandering zombies. Hordes are great, but being able to run around at night, knowing there are no zombies, is something i think you should counter.
Currently when you clear an area of zombies, none spawn unless you have forges going. Why not keep spawning them? An empty world isnt a fun one.
Thats my 2 cents on the whole zombie spawning/behavior thing, but i still feel the old AI was better at breaching and keeping the long-play games fresh. I bet people now can probably complete a 'unbreachable' trap setup in less than 7 days which would last at least 100 days. This kills the game for people who discover that 'cheese-build' which there WILL be because you made the Z's predictable.
To put in perspective, my best memories of 7D2D was this:
4 player team, zombies spawns set to maximum, we had a concrete wall and 3 layers of spikes outside, its day 120something on a horde night and things were getting tough, the horde charge at one of our walls (random side), spikes deal with some of the weaker zombies, but the traps wear down and start to break, a vast pile-up of feral zombies and more start to destroy the concrete and eventually breach, leading to a tight stand off in which we had to fight the horde head on for the last 3 hours of the night, 2 of us with sledgehammers, 1 with a sniper rifle and 1 with the machine gun. The fight covers our garden and we retreat into the house, shooting from windows and slits, the door is breached but we finish them off at the door...3 of us heavily wounded, 2 bones broken, 2 near death experiences, and 3 infections.
If this changes to:
Setup a maze of death traps and watched them all die. Repair/maintain trap setup.
Then honestly i regret to tell you that i just cant find fun in that...more work than fun really.