The tribunal system is the same system used for every other athlete. It may not be perfect, however it is better than the non-stop speculation.
The trial would have been covered endlessly by both the mainstream and sports media. We'd have detailed, blow-by-blow accounts of who said what, and we'd ultimately have an impartial figure decide who he believed most, Lance or the USADA. Unfortunately the public haven't had that, so we're left in this state. There's just as much speculation as before, only people are now arguing why he did or didn't fight the charges.
And again, I believe it is more than just Hincapie's word, or 10 riders' words, or 500. The USADA wouldn't have pressed this unless they had concrete, because of the argument you put forward. They would have known just as well as you or I that if they sat Floyd Landis down and had him bitch nobody would have taken it seriously. If that is all there is to their case then I'll admit that I'm wrong, but I doubt the USADA are that fucking stupid to only have that as evidence. However, even if they are disgraced riders, they do not become completely untrustworthy. Perhaps alone yes, however when we get to 10, 15, 20 people saying "he's a cheat" I think we have to take it seriously.
EDIT:
There are now reports that the USADA have positive samples. If that's true then it'd support my theory that the USADA have more evidence than just testimony.