Without getting too much in the argument, I have to say that a tennis player (or football player or soccer player or anyone that has to be in a position to change the direction of CM very quickly) would have a good laugh at this thread. To seriously think that it is more effective to change CM direction from a narrow stance is silly.
Cheaps, I am sure you realize that the rate of change of direction of CM in skiing is VERY SLOW compared to many other sports. That is the only reason why your argument may be valid. If you truly had to change the direction of your CM as fast as possible (say, to get to that ball in a tennis match) your stance would very wide and your CM would be very low. The upright, narrow stance may be fine for small inputs to changes in balance, but it sucks for powerful, quick changes in direction.
All I am saying is that Bob's argument is technically correct. Skiing however requires relatively slow changes in CM direction so the lines get blurred and several arguments can make sense. But the fact is that Bob is making a point that is technically sound.
Anyway, narrow or wide, fast or slow, gang or cult, it would be a blast to ski with any of you. Maybe at Fernie. Maybe. I am working on it.