Let me start off by saying that I have been playing Assassin's Creed games since the beginning and love Odyssey for its content.
There are many gamers who stubbornly say that Odyssey is not a true Assassin's Creed game. I would like to point out that chronologically speaking, Odyssey takes place 450 years BEFORE AC Origins. We shouldn't judge Odyssey just because it has no "Assassin/Templar" plot. It does focus on the Isu/First Civilization influence on the world and the descendants of Isu/human hybrids.
The Legacy of the First Blade DLC does focus on the "first Assassin" and how Kassandra/Alexios's descendants became the precursor Hidden Ones. It does bridge the premise on how modern day Assassins have Isu DNA to handle the Pieces of Eden.
The Fate of Atlantis DLC does give some insight as to how the Isu civilization MAY have looked like 75,000 years ago. It was definitely cool to see what Atlantis MIGHT have looked like before it was blown to smithereens. I am also a fan of Greek mythology so playing this was enjoyable.
I would say that if you are a fan of Greek mythology and like to play a character with "special Isu heritage", then Odyssey is the game for you. There are some minor conversation scripts that didn't make sense when I completed some quests out of order but it didn't really bother me as much since I tend to skip cutscenes. The only minor quirk is the bounty system like if you are seen assassinating or killing a bandit/thug, you are considered to have committed murder. This was the only thing that did not make sense but otherwise everything else was tolerable.
Even though this AC game is more like an RPG than the traditional Assassin's Creed format, I think it was cool that I was able to build my character to one shot assassinate most NPCs. Even though I did not have the iconic hidden blade, the Spear of Leonidas still did the job and I was able to leave no trace. The Rush Assassinate ability was pretty cool. Overall, I was able to customize the skill tree and abilities to my assassin playstyle.