Personally, heretical as it may be, I like the AAB, because the B is the resolution and repeating the resolution seems redundant. I don't know, I can't explain it, but it works for me. In some cases, the B is very intense, emotional, whatever you want to call it, and repeating it would really rob it of its power, IMHO. Say the partita #6 gigue or the french suite sarabande #1.