I didn't like the FoF in Abyss either and I agree that the combat mechanics in the series are generally overcomplicated. But I've never been the person who needs to maximize everything or do everything perfectly and I managed fine on what knowledge I had. Like I didn't care in Symphonia about the best recipes because I was doing it for fun and it worked just fine. In Abyss I never needed to use the FoF to win battles, the game was overall pretty easy and what wasn't could be fixed with a bit of evel grinding, so I never needed to learn the FoF stuff

Not fussing at you, you like what you like, just saying for me it was generally a non-issue