After finishing my first campaign and going over to my second playthrough I must say that I pretty much feel the same. It's really demotivating to play through act 1 again and seeing all these plot beats with the knowledge that really none of it has any consequence in the end. You can't really resist the Guardian. You can't really make a deal with Raphael. You can't really find a cure for your tadpole. There's no point in not using all the powers it gives you. There's also the fact going evil feels so hollow now knowing that every evil choice I'm making is basically just going to result in less content for me in act 2 and 3. The illusion is completely gone because the choices that initially seemed meaningful and interesting simply don't really matter.
The illusion of choice is the perfect way to describe this game.
