We could go back to the time when the TdF organisers supplied the bikes (or was it just the frames) for all the competitors. We could ban derailleurs. Given the effort now required to prevent motors in frames this might be the last straw for machine examiners, especially in amateur races where the funds and officials are harder pressed but we could do it. Why not pennies and solid tyres (probably because someone will find that the riding position on a penny doesn't comply with UCI rules)? Will the racing be any better because of it?
I have often thought that there is a place for "Formule Libre" in cycle racing - no mechanical rules, no doping rules (possibly just the right to rip apart the bike of anyone you suspected of being motorised - or punch him in the nuts). Great spectacle, great entertainment. Of course participants would have to expect that they were banned from Olympics, clean sport etc because the assumption would be that they were all doped. At the same time all proven dopers (maybe even suspect ones) would be banned for life for the first offence.
FWIW my eldest daughter uses tri-bars. She has never been anywhere near a tt in her life (although she has the power in her legs to do well); she has tri-bars because she has weak wrists and it gives her a means of resting them. She also doesn't use drops for the same reason. Tri-bars no use to ordinary riders - go pull the other one!
OTOH I frequently feel that track sprinting was much more lively before everyone adopted discs. It seems to me that the variations in speed were more vivid somehow. Discs seem to reduce it to a challenge of force with little finesse.
Of course it's all a nonsense because the racing, particularly crashes, is much more spectacular in recumbent races.