I think the aluminum body is very hyped up by marketing, and therefor has received a lot of extra attention and criticism from "experts" all over the media and internet.
Aluminum has been used in car and truck bodies for quite some time. Yes there are some special procedures for welding repairs, but painting isn't a very big deal.
- The F150 already had an aluminum hood with no hype or fanfare, since the 1997 model year.
- Explorers had aluminum hoods and front fenders 13 years ago.
- GM put aluminum hoods on cars quite commonly even in the 90's.
- Big GM suv's have had aluminum lift gates for a number of years
- GM even did aluminum hoods on some G-bodies back into the 70's.
- Not to mention all the Jaguar, Land Rover, etc vehicles that have been coming in aluminum for many many years.
- Aluminum panel vans never get repaired or repainted?
So why all this fear of something "new"? It's not even really new, just a lot of marketing pizzazz involved.