Dear wulsy,
Great point, but what do you think the capabilities and golf demographics of all that read these posts are?
I see beginners, average capability folks, advanced players and probably even elite golfers looking at this site frequently.
One thing I think that is common for all however, is the hope that some 'nugget' they read will help them improve. So I find it impossible to conclude one solution may be right for those 'good at golf', could possibly be right for all.
In fact one other thing that SHOULD BUT IS MUCH TOO OFTEN NEGLECTED IN THESE POSTS, is that golf is a game of distance, and ACCURACY, so when we now consider the elements of how the body creates a swing, from a beginner to an elite professional several interesting things become evident, especially when considering both the improvement desires in both distance and accuracy.
So, based on admittedly limited testing, my findings are that the use of the trail hand to enter into adding energy to the swing, has a very significant 'potential error producing' effect, and one that if allowed to continue as a baseline, takes much more practice and lesson time to blend in with the distance and accuracy of the lead arm. In comparison, the 'dominant' lead arms shoulder complex and torque generating capabilities deliver adequate distance, but with MUCH LESS ERROR GENERATING movements.
My suggestion, start with a lead arm preference, measure the accuracy/repeatability and level of natural trail hand/arm participation, and add trail participation GRADUALLY until an elite capability IS REACHED.