I have been flying for 30 years and like all the differentiation that has happened. 

I happen to be very tall (6'6") and agree that the legroom in a standard seat is inadequate for me. I pay the fees to get an exit row. Before differentiation, I was forced to sit in seat with inadequate leg room. The seats with extra leg room were dished out on a first come, first serve basis. I am happy to pay. My only other choice back then was to book business class which I could not justify.

With respect to luggage fees, I always go with carry on and avoid the baggage fees. I believe this has lowered my cost to travel and forced me to be a more efficient traveler. Baggage costs companies money in labour, space, and fuel. Charge those that use it. 

Overall we should also consider that airline travel has become very reasonable. As a child, we traveled to Europe to see family. My dad says the tickets were about $500 a piece in the early 70's. With inflation is significantly less now.