I have the opposite opinion as you.
Throwing away the initial premise of a story can be good, and this manga had executed it very well. The removal of the watch aspect has upped the stakes, since Yotsuha can't just go "Oops, this is bad. Time to go back in time".
The Clover mastermind is great as well, because I'm intrigued as to who they are and what they're motivation is. The pettiness and cruelty is fuel for me to be even more intrigued.
And like my first point, the story is far from being dragged on. The removal of the watch is like the start of the next season, the stakes are bigger right now.
True, I don't think making the watch less reliable, or straight-up busted, is a bad idea. Yotsuha did get rid of the most immediate dangers to Uichi's life, and he himself seems more stable now.
I just think there's only so much misery and despair you can throw at one character before it starts to feel a bit silly and unrealistic.
Obviously, we don't know the full extent of the mastermind's abilities, which are likely supernatural considering the clover motif, but they seem so ridiculously driven, incredibly well-informed, and hyper-connected that any eventual reveal of their identity might end up feeling unsatisfying.
This story, while entertaining, has always leaned more toward shock and spectacle, and that kind of manga can only go so far before it becomes overly excessive.