I would have bought rMBP back in December when I upgraded, but I decided the convenience of an integrated DVD player (and to a lesser degree the price) outweighed the retina display. I bring my MBP with me when my family travels, and I like the ability to play RedBox rentals on it. Pick up a movie in one town, play it on the mac in the car, drop it off at the next town.
iTunes doesn't compete there. I can either plan ahead and rent the movie on iTunes before I leave (inconvenient and overpriced), or stream them over an unreliable LTE connection (annoying and expensive), or the RedBox app finds a movie for me somewhere along my route and reserves it for $1.29
And a DVD works in my hotel room regards of how crappy the hotel's wifi is.
I love MacOS, but Apple is in a wrongheaded drive for as thin as technically possible, and to hell with everything else. What happened to finding the right balance?
By the way. I have a rMBP for work. I really like the screen and the SSD. I couldn't care less that it is thinner than my personal MBP. Offer a thicker version with a DVD/BlueRay!
And SSDs are still too expensive. A thicker body would be really beneficial if it allowed them to put a fusion drive inside a MBP. Or they could always put in a hybrid drive. The only time my slow HDD bothers me on my MBP is when booting or waking. A fusion drive should take care of that nicely.