This is an understandable desire. The lack of upgradability includes the lenses themselves, but not simply because of the LED configuration. Per an EcoTech Marine employee, there are technical limitations to the tolerances in the fixtures prior to the G4 that prevent them from realizing the benefits of an HEI lens.
Absolutely understandable, but G3 owners have a right to be upset. Ecotech should've stopped saying the G3 was upgradable on their website the moment they realised it wouldn't be.