No to first round RBs. Why spend that capital on a 4 year player?
Great, you might get an elite player during their rookie contract. Then they want to get paid. But RBs break down notoriously quickly and their best years are usually behind them at that point. Off the top of my head, here are the recent top RBs that actually received those extensions.
Ezekiel Elliot, David Johnson, Leveon Bell, Devanta Freeman, Todd Gurley...
If you want to take the bet that your guy is an ageless wonder like Adrian Peterson, be my guest. But I don't want any part of the extensions I've seen given to these RBs.
There are plenty of guys that can get the job done that can be had in the 2nd/3rd rounds, or even later.
But the first step in handing out these big contracts to an almost guarenteed declining asset is to spend a high pick on one.
Build up the rest of your offense using those first rounders. RB is not the way to go.