and Jon Jones moves up to immediately challenge him for the title, would you give him credit for that if he wins? Would it be better or worse than GSP beating Bisping?
In the Arizona Cardinals went 9-7 in the regular season (barely a winning season), but made it to the 2009 Superbowl, where they lost to the Steelers -- ie a very average team making it to the Superbowl. Do you give the Steelers credit for beating an average team, or do you consider that not a real Superbowl win for the Steelers?
If Lewis has enough good days to win the HW title, and then Jones beats him, then Jones will be the HW champ, just like the Steelers were Superbowl champs despite only beating a 9-7 regular season team for the title.
Sometimes in sports teams or individuals have good days at the right time (the 2008 Cardinals, Bisping beating Rockhold), and get to the championship despite not being one of the two best. The team or individual that beats them is still considered to be a champ. Not necessarily one of the great champions, but a champion all the same.
The real farce in GSP vs Bisping was that GSP (who hadn't fought in four years) was given a title shot in the first place (he hadn't earned a title shot at any weight at that point, not at MW, not at WW) -- no real sport would do that. But once the UFC agreed to that travesty, GSP winning it was a legit win.