I've been playing AC since I was a teen. It's been pretty hit or miss with Ubisoft in the last decade, but Shadows really is a hit for me. The graphics are stunning, the gameplay is really fluid, and overall, the game is FUN. Being an adult now, finding this kind of excitement for a game is rare for me.
For maximum enjoyment, I recommend playing in immersive mode or just Japanese (English makes it kinda cringe), and play on normal or hard difficulty.
The hate for this game is unwarranted, and most 1 star reviews are kids hopping on the hate train because it's trendy to hate Ubisoft. I'm rooting for Ubisoft to succeed, and to make a comeback as a company with games that follow in the footsteps of AC Shadows. I don't see a problem with that. Everybody wins.
I'd say give this game a shot. It will be worth your time.