what's 'necessary' though? If you boot up the game with a buddy and play it it's going to be a fun action-packed game w/ each guy hitting a couple of dingers etc..
That's why there maybe should be some slider pre-sets w/ a default to what i think would be the most popular being 'fusion' which would be sim/arcade combo.
The sliders are the for you to customize your game experience. Perhaps the sliders are better the way they are by default than the opposite? If someone want a quick game and doesn't have time for franchise and slider tweaking - if it was the other way around, that guy would have to do a bunch of slider tweaking...the way it is now, only the harcore sim guys do.