Just for the record, and I hope this confirms a few points raised.
The stats are based on player stats, which I think is the fairest way of doing it. On paper, Souths starting line up, would have performed better, but injuries during the season affected the team's result at the end (and as well as the internal hassles etc).
I played the whole season with a little experimentation, swapping the odd player, as I felt needed to be changed, and despite a few losses, I won the Grand Final. So it can be done.
As the game can be customized etc, you can do pretty much what you want, but I have always tried to stick to the original teams, rather than mixing players from different teams. I don't have as much time as I used to, and I like to sit down with a beer and enjoy. If I have to fiddle to much I start to lose interest. Sometimes I would wake up at 4am in the morning just to play the game.
But anyway, with practice, you will get better. I am no games whiz, but I have certainly played a few over the years. I suck at Pacman, but will whip anybody's butt in Galaga. ;-)
Other things may change the course of a game. EG kicking out on the full. Dropping the ball, or a 40-20. I played 1 game and was behind 12 nil at halftime. Then, a mistake in my favour, and it was a whole new game resulting in a victory my way.
So you will find out for yourself when the game comes out, and come up with strategies, skills etc.