Seems like a pretty open-ended question. Based on your need, then yes and no.

Is more clearance better for MBing? While it would see that mud and other small debris would clear the gap, what about wedging in a stick or branch and then getting thrown? Wouldn't a smaller gap force the object to snap?

If you are commuting, then obviously you want a solution that allows you to ride on the tire of your choice. There is no such thing as "proper width tires" though. That's perception. I know people that can commute on 23s as easily as they could on a pair of 2.55 MB tires.

I like the clearance for weekend riding on my CAAD with 23s. I like the clearance on my Araya with 32s.