If you dispose of the idea that current Zeke compares to young Zeke, then the Cowboys are not necessarily in the no-man's land most pundits seem to believe for their running game. They have elements that could lead to a good running game on offense - even if they don't have any superstar caliber players. If they are willing to actually use Luepke and Vaughn regularly (5+ carries each) per game, then Zeke and Rico can handle the other 25 carries between them. Throw in 2-3 jet sweeps from Turpin and an occasional end around from CeeDee and the Cowboys can have a competent running game - which is all they need.
The biggest factor which will contribute to a strong running game from the Cowboys isn't the running backs in the RB room - it is the new beef upfront. The left side of Guyton, Smith and Beebe could become a force, and two seasons ago, Steele was the Cowboys best graded Olineman in the running game. Martin on the right side is still strong. Uprading the strength in the center of the Oline is going to be a huge factor in the running game. Even last year, the Cowboys did better running the ball when Brock Hoffman was in the game. He was simply stronger than Biadasz. Biadasz is still a good center - above average even. But he simply never had the strength to open up holes in the running game. Biadasz has the feet of a good Olineman, but simply not the upper body Brute Strength. This was why so many coaches were high on Hoffman coming into the season - because of his strength. He wasn't as technically good as Biadasz, but sometimes you simply need the brute force. Beebe has both.
The Cowboys are going to struggle in pass protection on the edges. Guyton is young and will make mistakes. Steele is still a work in progress. That is why having Zeke in the backfield to help out isn't such a bad thing for passing plays. But both tackles are already pretty good run blockers who love to punish defenders. Add in two All-Pro guards and the Cowboys run game could be a huge surprise for a lot of people - simply because the Oline may consistently get a 2-3 yard push off the line before even talking about opening holes. Those are some big strong dudes up front. As they go, so goes the running game.