Regarding competitions, I definitely think every cyclist has to ride the same type of bicycle, technology-wise, but I'd love to see competitions using alternative designs.
One area where I feel like is also an interesting comparison and where I thought ronaldx was going with this is around performance enhancing drugs and the UCI. I wouldn't be the least bit surprised to learn that things that Vettel being accused of now are, strictly speaking, not against the rules but clearly creating an advantage. The innovation is in the details in the same way that the drug regimens of many cyclists throughout the last couple of decades in many cases did not include drugs listed on a banned substance list (e.g. early blood doping '70s vs. became illegal in '86), because the UCI and WADA simply didn't know about them. It will be interesting to see if Vettel is found to be playing in this gray area how he and Red Bull will be judged.
*Please note I do appreciate there is a big difference between doping and mechanical advantage through design, just thought there were some interesting parallels there too.
Though tease rules where implemented when steal was the only frame material you can build strong and safe bikes well under the UCI minimum nowadays