The thing about playing an individual season is you will never have the choices that you have in ATG-- ATG has tons of choices--it's a flaw and a selling point.
These are the players the real teams had to deal with-- and there were twice as many teams. I think in a way this is much more challenging. You can't just plug in Frank White or Crosetti if you lose out on the stud MI's.
I think, the downside is--it will be relatively easy to "figure" this game out. Probably only one or 2 different strategies will work. My guess is that this game doesn't have much staying power. The autodraft could be a huge factor here.