I will note before starting that I have only played, and plan only to play, the Co-Op mode of Insurgency: Sandstorm, so all the nitpicks and experiences listed below will pertain only to that area of the game.
Although the difficulty of the AI is greatly improved and thus increases my enjoyment of the game in general, I feel that in a few specific scenarios the AI has been made to be too powerful against the players. The aforementioned situations hinge mostly around very close quarters defense. The bots' new grenade mechanic they use to attempt to destroy defending forces is refreshing and invited, but it seems their grenades are usually impossible to avoid. By impossible, I mean to say that a player is physically incapable of reacting to the sound of the grenade hitting the ground quickly enough to escape it in the majority of situations wherein the AI decides to throw a fragmentation grenade into a defender's window. This is because in conjunction with the naturally quick timer of a grenade, the accuracy of the AI's throws are impeccable, meaning that a grenade will more often than not fall within a meter of most of your team. Things like that happen more often and are more detrimental to the players' fun in smaller cap zones, so I would recommend maybe forcing the AI to skip the script, or what have you, that causes them to throw grenades into the area a defender would currently inhabit if it is a one-level building or structure less than five meters long and wide. My other major qualm is the frankly atrocious ability of the AI to walk around a corner, get shot multiple times, and instead of balking behind the corner or dying they press on to get a one-hit melee kill against someone who shot or is shooting them multiple times. Firstly, this does not account for the fact that poking someone in the head with the barrel of your gun is more likely to hurt the gun's accuracy than the person being attacked's health. Secondly, you have no chance to struggle back. Now, I don't know if you've ever seen hand to hand combat but I will inform you that in the vast majority of the struggles I have witnessed, they are not concluded with one person standing victorious until at least 3 full seconds have passed, and this is at the extremely low end of that spectrum. Usually, hand to hand struggles will last far beyond 3 seconds and maybe even to a full minute. A simple fix would be to force the player to mash a button until they fill a bar, and for a simple first person animation to play either concluding with the player or the AI stabbing the other in the chest depending on who wins the struggle.
Also, as another note, I believe the AI's accuracy could be slightly bumped down, as in 5-15% more misses and it would make it more fun for the players while not being too easy. This however, I find to be unnecessary where I class the higher 2 problems as wholly necessary, albeit with a layman's solutions attached.
Thank you to New World Interactive for making three amazing games I love.