To make bots better at the higher difficulties in chaos wastes, I would give them some sort of power level increase (25, 50 or 75 really anything would help) whenever the host receives a boon.
This would somewhat mitigate how overwhelmed they typically get at legend and cataclysm
Just make them scale with host so when host upgrades weapons they also get their weapons upgraded accordingly temper or exchange. Also when host gets boon they should also get one. Or just let host buy stuff for them with coins that bots get(which they should). This could also help players joining mid game, imagine joining last level of expedition and your gear is white and u dont have a single boon.
Currently, bots are absolutely underequipped to deal with the wastes. Their AI most likely always will be.
If anything, they should start with their full loadout from the base game so you can make them as defensive as they need to be. They also make a lot of coins go into the void, which should be stored for any joining players at the bare minimum.
I figure they´ll be useless in the wastes no matter what due to the population of specials&bosses and how the they interact. Unless their code gets rewritten into making them real hardcore…
I think their ai is ok for the most part, it’s just they are stuck with crappy gear and can’t get any boons which results in them getting demolished when the spawns get crazy in the waste.
I believe this is the only reason why you can do normal maps on legend and cata; they use the last build you had on that character which is usually fully decked out.
My cata bots die the second there is a horde + 1 gasrat/gunner or stormer since they´ll pull out ranged weapons and just run over in that direction or not dodge it at all. I really do not feel much hope for better stats fixing those.
And post some point they also lost nearly all skills they had for dodging boss hits and now easily eat hits from those too.
Tbh, the only way you could make bots usable in such situations is by straight up making them invulnerable, since their dps output is not going to turn the tides anyway.
Or training some advanced AI on thousands of recorded runs of modded difficulties 
Back when the bot improvment mods was launched they actually were useful as long as it worked, they could snipe specials without running around the map and they could fight.
“Could fight” as in not blowing abilities on 1 slaverat, ignore enemies around or not ress people, heck,they could even tag enemies.
Those bots compared to the ones we got today? Aint no comparison.
Back when the bot improvment mods was launched they actually were useful
My biggest problem since I got back into the game after almost a year break. 2020 with the bot improvement mod was great, they could tag enemies, snipe special when they were in their vision not when they were next to them, when assassin jumped on you they would use range weapon to snipe it instead of now running with range weapon in hand towards the assassin, changing to melee while standing next to it and hitting it and they could res you - so many games right now when bots just look at you when youre downed and not even try to res, getting downed with bots is game over basically. They wouldnt use ult as soon as they see one enemy. But I guess that’s what we get when devs dont want bots to be good since its coop game and youre suppost to play with ppl not solo with bots.
The bot mod was great I agree. I was very disappointed when the patch that brought bot improvements didn’t include the ability for them to tag enemies. I mean, they’re obviously able to do it so why not allow them?
Vermintide bots are actually pretty good compared to bots in a lot of games and I think with some qol additions like this they will be in an acceptable spot.
The Bot Improvements - Combat mod has only three specific bot behavior modifications as stated in its description. 1 - Better Melee Choices, 2 - Stay Closer, and 3 - Ping Elites (which currently does not work with the game).
All bot behavior outside those three are not because of the mod, but due to vanilla game bot behavior. This includes whether or not they ignore/target an enemy, how they use their ult, decision-making on when to revive, how they target/snipe specials, among other bot behavior.
The bot improvements mod does not affect that behavior. And that bug has been happening even before the Chaos Waste and Bot Improvements updates (Patch 4.2). Bots have always had a propensity to chase after specials with melee weapons.
Here’s a 2020 pre-Outcast Engineer and pre-Bot Improvements update screenshot of me getting stabbed by an assassin rat while the three other bots wander off to melee another special (one bot actually passed by me and ignored me).
Bug reports reporting similar bot behavior have been posted since 2018 (the year the game was released):