I agree the biggest thing missing is the feel, in gliding for instance I would never look at the variometer, a bit of negative g then a soft, sometimes hard kick in the butt indicating a thermal.
I've flown right and back seat for SE since I was 3 years old, flown gliders, power from a Tiger Moth and Grummon Goose on up to SE's 402, but my greatest thrill was his Pitts S2A. Aerobatic flying is nearly all out of cockpit reference and I believe sims teach you the mental basics, procedures etcetera. With a control tower helping in an emergency, a good simmer would have a good shot at walking away from a landing, solo, man he'd be lucky.
There's no auto level for when you get in trouble and no auto take-off, but, you know about torque and how to deal with it, someone without the sim experience wouldn't have a clue. Sims teach what the gauges do, what they look like, all very important basics.
Psyco