I've only beaten the game once, so I'm not sure how these things work with expansions. I'd like to play through the new expansion content with the Crusader, but I don't want to play through the first 4 Acts again. Is this possible, or is it inevitable that I'll have to repeat that content? Also, how long is the expansion compared to the original game? D3 has 4 Acts, whereas RoS only has 1 Act, correct?