To each their own. We all weigh different weights, ride differently in different areas with sleds setup differently. I have used several aftermarket shocks and love the ability to fine tune the ride. This year I'm riding on Polaris stock piggyback shocks. Stock shocks are getting better but they are not there yet. I think the sled manufacturers are spec'ing shocks as light as possible to keep a low dry weight. Revalving is a great option too, I'm just not as familiar with the Doo shocks.
If I did a Doo, I think I'd get an SP and add shocks. But...you can't get that cool new blue/green combo!
Actually they valve the shock to sit in the right calibration for the rider weight that they pick and go nicely up and down from there...if your a pip sqeek like me or a fat bastard, your gonna find they are not perfect for you. Carl Kuster one of the best sledders on the planet, who regularly jumps the 174 80-100 feet just uses stock shocks revalved, he never complains their not enough. I rarely get off the ground so my shocks sit at 1 all year long.