Another factor to consider is also the durometer (hardness) of the wheels relative to the grip available given by the surface. My background is as a slalom skater rather than a longboarder per se. Therefore I am more grip-orientated rather than slide-orientated.
Temperature is also a factor too, as in very warm conditions, a soft normally grippy wheel will mush out and slide like a greased pig, where a harder wheel won't deform and grip like poo to a blanket.
Wheel profile too can decide whether a wheel will grip, slide and go or slide and lock back on.
Technique-wise, it would be cool to see footage as if you are inclining rather than angulating, you will actually be applying lateral rather than downward pressure and forcing the board to slide. It would IMHO be almost impossible, without the use of an inclined bank, to EC on a longboard because where a snowboard edge is embedded in the snow, the wheels are resting on the surface of the ground and therefore cannot achieve the same level of grip.
That's my gut feeling, but I'll give it some more thought...