its not exactly one of my favorite games, but honest question: What do you mean exactly?
I personally stop playing pretty often because I myself am just bored and need new games to enjoy rather often, but I'm genuinely interested in what aspects make you say that it fell of

Back then I was way more lenient on the bloated story telling (wasn't really that bad) but at Sumeru it just became unplayable for me there's like 6 acts of you just doing what felt like nothing. Inazuma was the peak of the game but after that it fell off quick, esp with the lack of fun gameplay I just don't rly care anymore.