I read this thread and decided to see for myself what I must have been missing.
I have spent the whole day in the ack, making different approaches, dying a hundred horrible deaths. This is what I found-
I could climb relatively safely while under the ack umbrella, so long as I wasn't right on top of the fleet. I could climb to 10-12K, split-S and divebomb the fleet with an F4. So long as I didn't get too low I could usually pull out and escape. I eventually got a CV today when I worked this all out.
Now I died many, many times- to the fleet gunner named "Hector". That's right, the human got me far more than did the CV ack. I did get hit by ack and killed once, but considering I had spent 1 1/2 hours in the umbrella I thought it was more than a fair trade.
Later I took a Lanc to another enemy CV. I made 6 passes over the CV, sunk it, and only lost a flap. This I did from 20K (testing the upper limit of the suggestion).
I am not saying you guys are wrong, only saying that I haven't seen the problem as that big yet. I hate the ack, but after today it doesn't worry me near as much as it used to.