It’s true that Sport mode provides superior racing, but the downside is that it costs a lot of time for comparably little racing. When you’re firing up your PS, you first need to put in a decent qualifying to ensure you’re giving yourself the best chance to protect your ranking, then most of the time you just missed the deadline for a race and you end up waiting a lot. Offline is just click and go. For many people that’s the more appealing game mode most of the time. I think the reason it wasn’t included from the beginning was that they wanted to force people into Sport mode. In the long run the game always needed a Campaign mode and custom arcade races. Campaign mode is also nothing like the Mission challenges, because you can choose your car, thereby altering difficulty. I just wish they would include an AI difficulty setting and the possibility to turn off boost.