I agree that in theory, the standard could come down just a little, but I don't find cars weighted to NMRA standards to feel heavy to the hand. The one variable that keeps the need for less weight down is track quality, which no one but the modeler can control, with excellent track product choices, great track laying, and a decent choice of layout venue, i.e., not the garage.
I just weighted all my cars to NMRA standards, and find they run and really push back in switching, much, much better than they used to. I also do notice when I push a standard length train by hand that the extra .1oz per car I might have added does feel much heavier. So, loco pull is an issue, but I never eally mind adding a unit!
I believe consistent weight per inch is the key to good running, so the standards could be changed a little, but I wonder if in the practical world it would be more than 1/100th of an oz per inch? So, I would leave them as is, and if modelers just made their choices based on their own track, layout locale, etc., to make their own standards (as most now do anyway) then there is no real harm done. But, there is no harm done leaving them as is, so those who are members of clubs that use the standard don't have to make big changes.
