yeah boxing PPV's still need to step it up a bit, mostly it's just Golden Boy PPV's that are weak though, because it's all about the main event which are normally super fights, and the undercard they just showcase their up & comer fighters against some bum to make them look good.
It's also because in boxing, the stars make soooooooooo much more money than MMA fighters, they can demand a huge majority percentage of the purse, so that means there isn't much money left over to pay the undercard fighters (thus why you see a lot of up & comer guys against bums).
But, the Marquez/Mayweather undercard should be pretty decent. Zab Judah is fighting, rumors are against Mathew Hatton (Ricky Hatton's brother) and Joan Guzman may possibly be fighting Juan Baby Bull Diaz (but that's unconfirmed). Judah recently signed to Mayweather promotions or whatever the hell it's called and rumor is Joan Guzman will be signing too (he trained with Mayweather sr. and mayweather jr. gave a lot of props to Guzman saying he's the closest fighter to him style wise). If those go through they should both be highly entertaining bouts.