If you're going to try and discredit the season Sproles had in NO, this discussion is pointless. Nitpick all you'd like, but the reality is Sproles had by far his best seasons for fantasy in the situation you are saying is the worst.
I don't think Vereen is a bell-cow RB, so his value is going to be highly dependent on the number of targets he receives. No, he isn't Sproles, but he's a heck of a lot closer to Sproles than he is a guy like Murray, for instance. Sproles didn't get many carries or goal line work either, but all of those receptions in a great offense added up to fantasy gold.
I agree than Indy could be good, but completely disagree that NO is the worst- IMO it's easily one of the best for him. To be clear, I'm not saying Vereen will duplicate what Sproles did, just that it would give him one of the best shots at fantasy relevance.