After playing AC Unity, I had little hopes that AC will be any good in the new generation, but boy was I wrong. AC Syndicate overhauled the combat system. If you've ever played the Batman Arkham series, it's exactly like that. Fast paced, and reaction based. Compared to the slow clunky combat system in Unity, you actually feel like a skilled assassin that can kick ass. You weren't overpowered like in Black Flag, where you could take on like 10 people at a time. But you weren't a push over either, overwhelmed by merely 3 baddies, like in Unity.
The hook shot is also another tool that was featured in the Arkham series. This tool makes it so much easier to traverse the city of London. You can zip across vast areas, horizontally or vertically. This does take away the need to climb a lot of things, but for such a large map, it's absolutely needed.
I loved the characters in Syndicate. They were funny, interesting, and varied. Can't help but to chuckle at some of the back and forth dialogue between the Frye twins. The game also incorporates some very notable historical figures, like Darwin and Bell, in awesome ways.
The infiltration missions allowed multiple routes and options, which was the only good thing they took from Unity. And the rest of the missions still felt unique enough that they didn't seem repetitive. Jack the Ripper was also one of the best DLC I've played. The fear mechanic was awesome.