I only started the Sassy Creed series like, two months ago and just recently finished Rogue (awesome) last week. Honestly, I don't mind the annual release thing, I like the games even if Brotherhood was crap and III was a loud "meh" but not terrible.
I will eventually play Unity once my PC is done being upgraded and then will probably get onto Syndicate. That being said, Syndicate looks like the absolute least interesting one to date. Dishonored without magic, the industrial revolution was dull, filthy and brown, and it looks like it's going to be another class warfare "Yay poor people, boo Aristos" story that we've played or seen in films about 100000000 times at this point.
Furthermore, since Black Flag and Rogue take place in modern day Montreal at Abstergo Entertainment, we know that nothing we do will stop the Templars. Nothing in Syndicate can possibly be achieved that won't be undone between it's setting and whenever the Hell the Templars decide to pack up and set up shop in Montreal.