@ carl r
I think you're at least partially right and I just did a bad job explaining things. In the right hands, a full bore race ski will be better than the cheater ski in almost all conditions. You're right in that radius doesn't make a ski intrinsically easier or harder to use, it just gives a certain size turn that it's best for. But, on a race course, a shorter radius is always easier (all else being equal). High torsional stiffness is always good in groomed skiing, but bad in park, pipe, jump, mogul type stuff and probably good for powder unless you're lazy. What can make high torsional stiffness bad is making it easy to accidentally catch an edge, especially with beginners that snowplow or do only skidded turns. The "carving" skis of 10 years ago are a joke by today's standards. Just look at old WC races and you'll see that those SL skis with 30+ meter radii couldn't make turns anything like today's latest and greatest. A FIS legal SL ski is easier to use than a comparable GS ski. That same SL ski is harder to use than a cheater GS ski because it is more physically demanding to ski aggressively on (any ski can be used with zero effort with concessions in line/carving) and will transmit your slightest move to the snow so if you stumble you'll get more thrown off. A cheater will get you further for the effort to a point, but beyond that point, the race stock ski will be better.
One point that I must disagree on though is damping. You are right in that most things marketed in the ski industry are gimmicks, but damping is still if not the single most important consideration in ski design beyond the obvious choices/restrictions associated with a given target use, it is certainly high on the list. Vibrations decrease your control of the ski-snow interaction, decrease edge hold, decrease the obtainable turn radius, and decrease speed in themselves. They won't directly make you fall over, but they will make you ski worse and falling comes with bad skiing. Unless this forum supports LaTeX, it's hard to really get into why my assertions are true. But for example, Fischer markets race skis with holes in the tips and cuts in the tails. They correctly say this reduces mass and thus moment of inertia, but this means shit for your skiing. It is however a good idea because if you look at the 4th order Euler-Bernoulli beam ODE, the 2nd order oscillation ODE, 2nd order wave PDE, the Cauchy stress tensor, constitutive mechanical properties, etc. it will improve things significantly. Race stock skis will damp vibrations worlds better for aggressive skiing.