One of the central issues with co-op IMO is the AI. While it is somewhat adequate, it really falls far off the mark from what would be needed to really make the co-op mode great. Simply put, the AI has far too many inadequacies that ruin player immersion and experience, and is in dire need of improvement.
The problems, as far as I can see them, are as follows:-
1. It is terrible at Defense
Simply put, the AI seems downright incapable of actually putting up a defense. It seems to have only one way of operating, which is to work as a rifleman. Every single unit, from the gunners to the marksmen try to hide in corners or stay inside buildings and wait for the players to come to them.
The net effect of this is that it becomes very easy to rush and overwhelm the AI using CoD style bum rushing, with no need to work together or otherwise use any sort of breaching tactics.
2. It is far too good at offense
This comes from a variety of factors, however, the most aggrivating of these are:-
A. The seemingly supernatural accuracy that the AI has at range while moving and immediately after moving, which allow it to practically snipe anyone not camping inside the point.
B. The ability to, for all intents and purposes, completely ignore the effects of suppression fire, making the gunner useless at creating kill zones and relegating them to sitting ducks for the AI sniping them from a distance.
C. The use of laser guided molotovs, which make using any sort of cover or positioning an exercise in futility. Simply put, the molotovs used by the AI add nothing to the experience, while considerably worsening the experience for the players. These are a rather egregious example of artificial difficulty, where the AI, instead of breaching or using things like frags and flashbangs, just outright kills the player in an unfair and arbitrary manner.
3. It makes Gunners pointless
The supernatural accuracy and practical immunity to suppression that the AI gets, makes the Gunner class practically useless in co-op for all intents and purposes. Add to this the AIs inability to defend and the Gunner really doesn't bring much to the table. Worse, the Gunner practically becomes a sitting duck, since they can't prevent the AI from firing back accurately while themselves remaining stationary, which makes them more readily shot and much easier targets for the AIs molotovs.
What all this creates is a situation that is the inverse of actual combat, where attack is trivially easy due to the AI never actually putting up a defense (which also enables the all too rampant rushing) and defense is much harder due to the AIs overpowered abilities and molotovs.
I would therefore like to propose the following suggestions to improve the AI and make the co-op mode more fun to play:-
1. Change the AI spawns when it is defending a point to be nearly on top of the point itself. This allows the AI to actually have a reasonable chance to get into position and put up a defense rather than just being barely able to reach the point and camp in corners.
2. Give the various AI classes more specific behaviours and better situational awareness (maybe put in an AI director), so that the classes actually do their jobs rather than all trying to do the work of breachers and riflemen. There's no use to an AI gunner who is only covering one corner of a room; the gunner should be laying down a hail of fire on incoming players and creating a beaten zone across an approach to the point, similarly, AI marksmen should be taking up vantage points and pressuring players rather than lying prone in a corner or breaching rooms.
3. Make suppression have a greater effect on the AI. AI should not have any sort of accurate fire when under suppression. A suppressed bot should only be able to spray wildly, if at all, and should be more focused on retreating or finding cover than trying to return fire.
4. Reduce AI accuracy exponentially with range. Simple as can be, the AI should not be making accurate shots at the players when at great distances as this only leads to frustrating sniping by bots who should not be doing so. A simple, and more realistic alternative to this wold be for the AI to try to suppress the player instead by concentrating inaccurate fire on their location when engaging at range.
5. Remove molotovs, at least from the AI. The AI using them adds nothing to the game, and deaths to them are the most arbitrary and frustrating parts of a coop match; especially since they universally come at impossible angles and with supernatural accuracy. There's no place the AI can not reach with frags and guns instead, and the molotovs just make the whole experience a frustrating affair.