This video analysis, originally posted by Tog in another thread, is also relevant because, for purposes of the current thread, I think it gives color on what McNichol means by "heavy."
As far as feeling weightless in transition, I'd make a couple points. First, for some transitions it's inevitable to get the skis to do what you want, for instance many times in slalom. Second, for really round turns while freecarving, you can feel faulted into the next turn even without losing contact with the snow -- so turn shape and terrain can play a role.
Most importantly, though, the camp most ardent about having a weightless "float" and not actively creating pressure on the ski, and instead waiting for the turn to develop, is at core a freecarving camp, with a lot of attention developmentally to pivoting along with a focus on carving the bottom of the turn. Nothing wrong with that, but it's a different game imo in terms of the focus given on those things developmentally.
Maybe second most importantly, yes most developing skiers would/will screw up the idea of actively extending initially if it's presented to them with that verbiage. If you present it to them as, for instance, a patience turn, or a bte to bte drill, to keep them task-focused without thinking about pushing hard, there are better chances of success.