Madigari, I never said Desmond's portion of the story was the main draw, but because it's not the main draw doesn't mean his story isn't the main story. As for the trilogy, it still is a trilogy, you got Assassin's Creed, Assassin's Creed 2 (including Revelations and Brotherhood as spin-offs or side stories) and Assassin's Creed 3 (and any other side game(s), or side story(ies), using Connor as the main protagonist). Main draw =/= main story all the time.
In most cases only numbered games are considered "main games", for example the Fallout franchise, New Vegas isn't considered part of the "main (or numbered) series", you can see this since Bethesda has a contract to make 3 Fallout games, they have made 2 games in the Fallout universe but only 1 (Fallout 3) is counted w/in their contract. Bethesda is working on a Fallout 4 and 5 plus who knows how many other spin-offs.
I don't mind anything about any of it, but what does bother me is that they use the metaplot to keep ending the games on notes that are basically screaming: "To be continued! Buy the sequel/DLC, chump!" Instead of actually creating self-contained stories that are connected.