The deal with doping back in the day was that if you had the best program, the best science, you could have an edge over people who just took whatever, whenever ...
Nowadays doping has been so thoroughly investigated everyone knows how to use all the latest techniques, masking chemicals, microdoses ..... how to dope for superior training as much as for racing ..... so it is more of a level playing field, I think.
Minus Seven was an incredible specimen, but he also had by far the most sophisticated doping program. Nowadays I doubt any team has a real advantage in doping quality ..... I also assume they are really careful to do just enough and not too much ..... and to avoid that nasty sudden-onset asthma that some riders seem to acquire. TUE or not, that stuff just looks bad.
And I think the UCI will let pretty much whatever get by them so long as people don't get crazy ... as in, no stages where a rider suddenly gains a huge amount of speed, smashes records up a climb or beats the TT field by a minute or more. After all, if people just Think the sport is still drug-riddled, but no one can prove it ... then it is as clean as any other sport.