I am SO very pleased now with how the AI 'behaves' with DC runs and searching for you after losing contact with you (when submerged). There's no rhythm or rhyme as to what they do or how they do it....it's like they are actually thinking of what their next move will be

This is why I love modding, especially AI
I just played cat and mouse with a veteran V&W destroyer, changing depth and speed erratically, for over 2 hrs game time. He would lose contact with me, start searching then acquire me again, do a DC run and I would give him the slip after his run....thinking I'm almost home free I up the speed a little and change the direction....moments later he picks a new place to search which is next to me...I drop speed but too late, he re-acquires me.....this went on and on and was SO fun!