Bought this game few years ago before it got removed from the market because of the Resynced. My quick thoughts on this experience:
Story didn't hook me until Sequence 10 or 11, though beginning was also interesting. There's just something off with the pacing in AC games, at least in the most resent in my memory - this one, III and Liberty.
Also, I completely forgot that Connor and Haytham are Kenway too. What an interesting family.
Sailing the sea is the most interesting part of the game. Even if we're not talk about the sea fights (which are great), the vibes are great when you go up and down on the waves, your crew is singing, a whale just jumped from the water to say hi, you then killing that wave... Okay, the last one isn't a part of the sailing vibe.
I especially loved the storms. Each huge wave was making me nervous for loosing my crew members. I'm telling yall, if I'd experienced the storm for the first time in this game as a kid, that would be the best thing ever. Unfortunately though, I expected to see more chaos during these storms like in The pirates of the Caribbean, not just these big waves and hurricanes. Still, it made Black Flag's open world more atmospheric.
Speaking of open world... It's fine. And you know what? It's a good thing for an AC game, because my experience with previous AC open worlds were overwhelming and, sometimes, unbearable. This is why decided to mostly go through the story in AC III.
The big part of why this open world works better than others is the fact, that you spend most of your time in the sea (or at least it was for me, because I almost never used fast travel), so you don't waste too much time looting every chest in the city. Actually, there are few big cities, but they are not comparable to other AC cities.
One of my problems in Black Flag is combat system. It's just the same as it was before. Or even worse somehow? Can't tell for sure.
In a game about pirates, where you have an ability to board enemy ship, you'd expect more than just "parry button --> attack button x10; break block button --> attack button x10"
