To be fair, AC games have never been about the boss fights. The mechanics are too limited to make any sort of 1v1 interesting.
It's a shame, because they're always building up the antagonist throughout the story, and then give them a Piece of Eden to boot. And it looks really cool visually, but damn if it makes for a disappointing finale.
The only time when this was okay, despite the game mechanics was the first game. Story built to a crescendo and it wasn't offensive because the whole game was repetition anyways. Plus, again, it was the first AC game, it set the foundation for the rest of the main game titles.
George Washington almost had it, but the fight was just a matter of patterns with no real sense of danger. Unity's was just sneaking up behind a dude three times and calling it a day. Awesome POE, but it's just a turret to sneak around. =(
One day they'll get it, I think. But not this year.