I greatly enjoy scenarios, squad ops, snapshots, and close escort -- those all have more realistic elements than does the main arena.
Still, I like the main arena a lot the way it is because it allows me to practice any plane I want in preparation for scenarios and the like and because, for periods when I don't have a lot of time available, I can jump in and get into some action quickly.
I also like the Axis vs. Allies arena, which I just played in for the first time yesterday, because it also is more realistic and was a blast. Massive Ju-88 raids, realistic plane sets, etc.
Combat Tour will add another level of realistic environment.
So, there is a spectrum available, from jump in and fight to realistic scenarios, and much in between. It is good to have this spectrum available so that all tastes are accomodated.