Let's address the negativity growing around first off:
Yes the games is short in comparison to Origins, Odyssey or Valhalla however those iterations were more RPG the true assassins creed. In this version a solid return to stealth has been achieved and with out the easy wins.
In Origins you can wipe out masses with flesh decay, in Valhalla you can empty a camo with poisoned sniper arrows. Mirage you have to play as an assassin.
Don't get me wrong, they were great games, great fog games but nothing like true assassins creed.
Now let's look at the Mirage game: It's awesome!
The game has good exploration, lots of fantastic historical facts and insights.
Back to the roof tops which is great. If you mess up the assassination you her to employ run and hide tactics which can be challenging at time with enemies being smarter in this game.
The parkour of brilliant with some new moves and new assassinations.
Gear collection is not as simple as the RPG as you need to solve puzzles to gain access, which in enjoyable.
The gear collection is also not exhaustive like it is in the RPGs where your constantly selling/ buying/ upgrading, in this game there is still some of that but it's more meaningful.
The characters are engaging and storyline is solid.
I really liked this game and will replay it many times.