Yes, you're right.
It seems that I went a bit over the top lately trying to improve the game experience. All this lines of lua code running around my head.

And I was just paying attention to the word "combat ai" and put up my normal '36 game experience with it. Wich is quite good with enough units.
I only noticed such massive redeploy behavour if the ai has not "enough" units.
Now that I reread the OP it is also clear to me that his problem must be somewhere else if it was way better with SF before and went only worse with FTM.
I'll make some tests now on my own on this too.
Maybe I can contribute something better then.
Cheers,
Chromos