There's no need to take a running back in the first round, but let's dispel with the notion that running backs grow on trees and that any team can pick some guy off the street and turn them into a 1,000 yard rusher.
Talent matters in the NFL and it's undeniable that running backs selected earlier in the draft are more productive than their later- or un-drafted counterparts. It's also fair to acknowledge that the position has undergone a drastic shift in value.
We've seen major devaluation in top tier RBs in the draft, despite their production.