I think it depends on the player. 3C can be a very valuable role, since he is often also the lead penalty killer, taking critical faceoffs, and matched up against the other team's top center. On some teams he may even be on the second power play unit.
I wonder what people are going to think of Backlund in hindsight. I feel like Calgary has spent much of the last 5-6 years looking for a number 2 c while they had Backlund being that.