For me, unless you have a top 5 RB like Barkley or AP, the best way to go is to draft mid round guys who fit your system and just use them through their rookie contract. If you get lucky and hit a home run, great. But put the resources into OL. A good OL makes all but the worst RB look alright, and a bad OL makes all but the best backs look like shit.
Howard is a good one cut, outside zone back. He doesn't really fit Nagy's system, they weren't going to keep him past this year anyway (rookie deal up) and they got a 5th rounder for him, much more than they'd get from any comp pick formula because he's unlikely to get a lucrative contract. Monty was a bit disappointing this year but he was also part of an epic systemic fail that flowed through the whole offense.