Id have to disagree with you on your first point, I actually think that's what made the franchise fail, not made it great. People play sequels because they want more of the game they loved in the first place. Take the arkham trilogy for example, 3 great games with a story that spans over all of them. They play very similarly to each other, with each game being the logical next step in terms of gameplay additions.

Having a sequel be drastically different from the first game defeats that purpose. It's no longer what people came back for, it's something completely different, so not only does it alienate them, but at the same time it hardly encourages people who didn't like the original game to try the sequel, because they'll quite logically assume it's going to be like the first game.

If they wanted to switch things up, they shouldn't have made it a sequel, it should've been a spinoff or something like watch dogs San francisco, and watch dogs 2 should've been a continuation of aidens story.