What's more important to the Bengals.....

[Bilbo Saggins]

I think that both lines have a little bit of a skew to their value. What I mean by that is that on offense you would rather have a whole group of average players than say one elite, 3 average, and one poor player. On the d-line I believe that you're more likely to get bang for your buck with an elite player. Take Kalil Mack for instance - he can line up anywhere and cause pressure for the defense. An elite left tackle can only control his man or his gap, leaving the worst player on the offensive line exposed. Basically, I feel that on defense you are most likely to notice the best player, while on offense you are more likely to feel the effects of the worst player. 

Both lines are very important, I just think that there is a bit of a skew as far as talent goes. "Average" and "solid" types of starters may be more valuable for the offense because of how quickly one bad play or player can sink things for the entire offense.