Let's say after Floyd beat Canelo, he moved up to MW to fight Sturm for the IBF title. Could Floyd join the likes of ODLH and Pacquiao as a 6 weight champion?
Probably, but neither guy fights outside their back yard, so I doubt this fight would have been possible to make. It would also put him in a tough position because GGG would be the next step, and he wanted nothing to do with that.
floyd was never a legit 160 fighter, but sturm was about as legit a 'world champion' as my dead grandmother. sturm was a heavily protected fighter who still lost multiple times to some pretty ordinary fighters. it's insulting to use their names in the same sentence.
Size matters. Sturm would have been 170+. Not saying he would have won, but I wouldn't count him out.