To tack on to CountryGolden’s comment about the user-friendlyness of customization, yeah, there could be some improvements. For instance, how about a way to save the current setup and have it stick? I rarely have only one instance of Rhino running, and often lose changes I have made to my toolbars because I forgot to close all the other instances before the one in which I made the changes. Saving the toolbar files does nothing if other instances don’t flag the changed RUI and offer the option to preserve or overwrite it.
I keep my customized toolbar files in Dropbox so I can access them from both work and home, and if I leave a file open at home and then make changes while at work, I have to remember to open a fresh file at home before I close the existing open one or I lose those changes.
One advantage to allowing users to tailor their setup is it permits those with larger, high res screens to take advantage of the extra real estate by adding more buttons to their toolbars. I would hate to be stuck with a lowest common denominator setup.