Before our CX-5 my wife had a 1996 Toyota Corolla, which is what we brought our son home from the hospital almost 7 years ago. We had rear-facing seats in that car and my 94 Integra (2-door coupe) for several years. We made do, and it worked out. Our CX-5 Touring is flat out LUXURIOUS compared to those cars.
For a 5'11 guy the true ergonomic posture would provide little room in back for a lot of current model car seats. People dont use ergnonomics and can make do with it - but its a discomfort. How often do you sit and drive in a car - very. How often do you need power lift gate - probably 30 times in its life.
For others who say he carries a lot of bags - ermm there are things like shopping trolleys and strollers that can be used. Unless you are buying from farmer's market where its all foot traffic and even then you can get a double stroller with a good storage space.
So as CX-5um said - if you are shorter than 5'3 or special needs than yes you need the power thingy otherwise it can be a feature that pushes you to buy a car but it can't be the primary feature you buy it even though you hate the styling / handling / mpg / other comfort.