It is my understanding that the focus should be how to minimise deceleration due to the increased effects of friction due to turning and the decreased effects of gavity due to turning out of the fall line.
I'd challenge anyone to come out of a turn faster than the went into it. If this were so then you would surely see WC athletes sticking in an extra couple of turns to generate speed.
What is felt is percieved as acceleration but does not result in an actual increase in the skiers speed over the whole turn. The loss of speed is greater than the gain of speed due to any tail pressure, etc...
I'm all for choosing the best line, balancing on the edges and staying centred.
My concern with trying to teach any pumping, jetting, etc... is that the skiers focus would be taken away from more important things such as staying centred, quiet upper body......once these things are in place then sure why not investigate a little to see if we can do anything to go a little faster.
On water skis you will accelerate when you turn but this is because the boat has not slowed and the skier is covering a greater distance its not practical to compare water skiing to snow skiing because in water skiing you are being pulled by a boat and in snow skiing you are reliant on simple forces of nature - friction, drag and gravity.
I've not analysed any other sports but I'd be interested to see the physics of skateboard pumping. Its worth remembering that it may be possbile to make movements that make something move from standing but with skiing you already have momentum. Could you take a skateboard jump on it on a hill and do something to make it go faster at 20mph?
You might want to read the Virtual Bump thread...you can skip to the last page were we are talking about this idea...