Does the two-back system work?

I read a fantasy report from ESPN's Neil Ravitz today that sort of led me to question whether the two-back system in Dallas works. You can read the piece here.

I personally thought that the Jones-Barber duo worked. There were times I was really annoyed at the short gains but I put most of the blame on the offensive line. Of course Ravitz takes a fantasy football spin to his synopsis and it doesn't work. Fantasy sports is a whole lot different than reality. In Fantasy NFL, Barber was a steal. Most people probably snagged him from the free agent wire in the first or second week. But, he was a role player, getting the ball often in red-zone situations. Parcells tried to use Jones as a finesse back and it didn't work all the time. I thought Jones heated up near the end of the season and he had a great game against the Seahawks.

Ravitz says:

"Last season, Jones averaged 4.1 yards per carry, while Barber's YPC was 4.8. That's a glaring difference, and not just for the obvious reasons. Barber actually had a handicap in this category because he received more carries in short-yardage situations. In fact, if you remove just the touchdowns from three yards out and in, Barber's YPC swells to 5.1, and Jones' ... well, he didn't score any short-yardage touchdowns."

The yards per carry is a significant stat to review. A 4.1 average isn't bad. But Ravitz argues that Barber is a better, more complete running back than Jones. I don't know about this. I think Barber and Jones compliment each other. They never seemed to be performing at high levels at the same time. I wouldn't be shocked if one were traded at some point. I'd have a hard time watching either go to another team. I do like them both and Barber is a favorite of mine.
I just think we need both to win this year and future years.