Note the repitition in the letter: 'light touch' and 'allow differentiation'. I think this is likely reasonable, but it certainly gives the carriers enough wiggle room to still play shenanigans. Which is likely fine; Sprint's right that there needs to be room for having differing services. But the good news is they clearly signaled that if they have to, they'll differentiate at the network layer instead of giving up at the services layer. (That's what I read into it - time will tell if it's merely a political gambit :)