Rogue might be the best Assassin's Creed game since Brotherhood, if you're invested enough
One of my favorite things is taking a story and extending it out, exploring it from every angle and examining every point of interest. I love sequels and franchises that survive solely on call-backs and references; it's pretty much the only reason I watch horror movies at all. So, for me, Assassin's Creed: Rogue has one of the best stories in the series, if not the best. I won't say it's the Forrest Gump of Assassin's Creed games, but it touches on so many different storylines that it improves other games' stories just by its existence. Where Unity is a game you can skip without missing much of anything in the world of Assassin's Creed, Rogue takes you on a tour of hidden treasures throughout that world. Outside of the Animus, the recycled environment feels a little empty this time around, but there are enough pieces of backstory to collect to make it worth wading through the unsettlingly clinical offices inhabited by annoying characters.
Even disregarding the story, the gameplay refines a lot of what made recent Assassin's Creed games fun to play and paces upgrades and abilities to allow the player access to most of them throughout the game, rather than leaving the best till last. Whistling from hiding places to draw in enemies was something I missed in Unity after Black Flag, so it was a great thing to have in Rogue. Also, the dart gun, which has been improved with a grenade launcher, allowing the player to affect a group of enemies in one move. The ship is given a couple of new features, as well, with the Puckle guns being a more pliable version of the Swivel guns from Black Flag, allowing the player to aim freely and fire more rapidly. It would have been nice to have the free-running from Unity, but the standard fare is serviceable, with familiar jankiness to deal with. I also enjoyed Unity's combat when it wasn't inside getting stuck in corners, whereas in this game I often found myself resorting to the smoke bomb to disable enemies long enough to stab them.
I think the thing I didn't like most about the gameplay were the stalkers, who hide in different spots waiting for you to pass so they can stab you. You can hunt them out with eagle vision, but if you're not paying too much attention or you're moving through an area quickly, you can miss that they're even there before their knife is in your back. The worst part is that they don't even do a significant amount of damage, leaving them as nothing more than frequent annoyances.
Overall, Rogue is a mostly familiar Assassin's Creed gameplay-wise, but it explores the series' chronology in a way that none of them really have before. For this, I love it.