I'm coming more to the conclusion that the modern "shaped" ski is a serious culprit in the "Intermediate Rut" Being able to just roll a ski up on edge and let the side cut give us a pretty arc tends to make us lazy. I teach golf too and once guy sees better drives coming off that Fat Head XL driver, he quits working on his swing. We get as far as the sidecut will take us, developing bad habits along the way and leaning to hard on the technology to the point like the golfer, "I need new clubs". Watch Jean Claude Killy in old olympic films. He was carving arc to arc slalom turns on skis with the same side cut as a XC stick.
What's usually missing are 1) Effective Fore & Aft pressure progression along the edges. 2) Absence of foot/ankle steering, and 3) Experience and a "feel" for the timing and blending of the 4 basic movements Balance, Rotation, Edging and Pressure.
Try this for me. Grab a tennis ball or baseball, stand up and place the ball under your right Big Toe. Starrting with the ball directly under your hip, roll the ball straight forward keeping the ball under the inside edge of your foot. Feel the progression of pressure as it moves along under your instep to your heel? Now, same position but instead of rolling the ball forward, roll the ball on a smooth round arc to the left.(please observe that your instep has it's own side cut) Can you see and feel what your foot are doing? How your hips have to rotate but your upper body has to stay still so your left foot doesn't move?
Grab a second ball, sit in a chair and place one under your right big toe and the other under your left pinky toe. roll both balls in a smooth arc to the left. Get out on some gentle terrain for some nice slow turns from a wdge. Instead of just stepping out with the new outside ski. Roll it up on edge and steer it around the turn the same way you did the tennis ball using your foot/ ankle and knee/hip to steer a nice round arc while slowly moving pressure from tip to tail.
Once you are comfortable with that hit some steeper green slope for a little more speed For now, make your front to back weight/pressure transition very exaggerated. Feel the front and back of your boot and lean on the ski hard. Feel the difference? Feel how the tails shoot you out of the arc? Cool huh?! The timing of for to aft in conjunction with rounded steering is what takes time to develop. As you start to get a feel for the timing you can slowly back off the exaggeration. If you find yourself skidding you are holding pressure on the front of the ski too long, roll your weight rearward mor equickly as you steer.
Go get some arch supports for your boots. Get some that are large enough you can really feel them in your boot. You may not want to leave them in all day but the instep is very sensitive campared to toes and heels and as you steer your arcs thru the snow, it'll feel a lot like the tennis ball and you'll have a better feel for where your weight is fore & aft
If you want some home practice and really want to upset the wife, put your boots and skis on in the living room and roll the tennis ball around! ;)) ...trust me...