MJD is easily worth a first rounder, but for what the Packers do on offense, backs like Benson, Green, and Saine will be more than adequate for the running game. All we need is someone who can keep opposing defenses honest, and Benson has shown he can be a workhorse back in that regard.
Packers have some big contracts coming up with Jennings, Rodgers, Raji, and Matthews nearing the end of their respective deals. We may need that first round pick to fill some holes because potentially, we may not be able to keep everybody. That doesn't even include guys like Saturday and Woodson who may not have a whole lot left in the tank in the next season or two. Receiver is really the only position imo right now, say a veteran like Driver retired, that the group wouldn't skip a beat as far as production. Can't say the same about the offensive line or secondary right now.
MJD would be a great pick up under the right circumstances, but Packers have bigger needs right now with their upcoming draft picks to give up a first rounder for a disgruntled RB who feels he's not getting paid enough.