I used to be such a huge fan of the Assassins Creed Series, but at some point during and after Assassins Creed 3, I felt like the series has been spiraling downwards slowly.
Unity wasn't what I hoped it would be at all, Rogue was okay but sadly really not more than that. I really liked Syndicate but felt like it wasn't all that important in the grand scheme of things.
Started to see some Let's plays of Origins and disliked it quite a bit. I can't really see Odyssey changing that all that much.
I know exactly how you feel, I was a huge fan as well, Unity was a bit of a let down and then they saved it with Syndicate and then lost it with Origins. Maybe it's because they are more concerned with pumping out a new Assassin's each year, rather than making sure the game is what the fans want, I would make rather patiently wait a few months more and get a great game. Yeah my first impressions of Odyssey was that they just took Origins and game it a new story and a new skin.
Another thing that annoyed me greatly, arguably the most annoying thing in general is the entire disregard for the present time story line.
I know that not everyone enjoyed this part of the game, but it was actually a major part of what got me and kept me interested in the game in the first place.
The present day templer/assassin conflict was interesting, but after Desmond died in 3, the whole thing ended up being pretty boring, bland and lead nowhere. Very sad.