The seeing through the clouds thing is true; I have ducked into the clouds to hide several times since installing 4.11.1 and have yet to be tagged (at least not until I came out at a predictable location). In daylight, the gunners on bombers and attack planes are considerably more realistically limited as well, a change I have waited for for 10 years. However, I find that once you've fired your guns on a dark night mission, they have entirely too clear an idea of where you are and where you are going even if you abruptly change directions afterwards (firing a two second burst and sharply sheering off still seems to get your fuel tank perforated at 2-300m by Rookie gunners about half the time). Since night missions are rare, I think I can live with that as is.
On the minus side, while I in principle applaud awarding ai pilots the ability to make deflection shots, I find myself getting whacked way too often on 90 degree deflection shots at ranges in excess of 400m, even when I see the set-up coming and quickly change directions (up, down and/or radically tighten the turn). What really chafes is when I go back into the full mission builder and find out that my executioner is rated Average or Rookie, and realize that Average or Rookie ai 'bot has performed the same level of long range, high deflection shooting on my aircraft in two or three consecutive replays of that mission in a row. That feels a bit as though the mission has assigned the Player a specific executioner that he must eliminate to survive the mission (and it doesn't help that the little SOB often turns up after you've smoked a couple of his buddies and are now running a hot engine and low on ammo).
That said, the majority of the enemy ai routines I've encountered so far are pretty good, and seem to vary according to type, which is a good thing. I've certainly seen a number of ai stalling out at appropriate moments (including my wingman, dammit) and often recovering in a convenient location for me, although I'd occasionally like credit for the kill when I have flown an opponent into the ground after a sporadic peppering with my LMGs.
Generally, I'm very happy with the AI changes. Bravo, TD!
"Here's your new Mustangs, boys. You can learn to fly'em on the way to the target. Cheers!" -LTCOL Don Blakeslee, 4th FG CO, February 27th, 1944