I'm sorry, I've heard the argumentation thing about seats at exit rows actually speed up evacuation, but I think it's tenuous to say the least, and oh how awfully convenient for the beancounters - don't you think.
Why do exit rows have more space at them than regular rows, why do some exits have no seats at them (like the main doors (front and rear))?? If the theory that wide open evacuation spaces hinder passengers leaving, and so rows of seat are added 'for safety reasons' then why do they leave so much space around some doorways and not others. It just doesn't wash, and the evidence supporting extra exit row seats is flimsy to say the least, and, I believe it has been stated would only be applicable in certain scenarios.
No, let's just get real, seats are added in to wing exit rows for financial reasons. It has b*gger all to do with making evacuation quicker, or passengers safer.