Earlier quoted context omitted.
I see no reason why any of those people benefit from the slightly thinner form of the new mbp than they would benefit from better battery life. Everyone wants batteries that last longer. How often did you look at your last generation mbp and wish it was thinner?
These people are lugging their laptop around all day, from meeting to meeting, or airport to airport. If you can keep battery life constant at ca. 10 hours, which covers an extended work day, then beyond that most people would prefer to have lighter/slimmer/cooler (less hot) devices than one that runs for 20 hours.
Regarding overall portability, I think the 13 inch MacBook air is a good compromise. The new 13 inch MacBook pro is about the same weight, but obviously a lot more powerful, and is smaller in dimensions. It's a breeze to work on planes with this machine.
I'd rather see the next iteration of MacBook Pros with better heat dissipation and longer battery life than with 1 mm improvement in thickness.