I certainly agree that the rambox isn't for everyone. For me it's much more useful than the standard truck beds I've owned. And the added benefit of having an adjustable bed divider which also converts into a bed extender just adds versatility. We also get an added 110 vac outlet in the drivers side rambox. As far as bed covers go, I had no problem finding a tonneau cover for my rambox bed. There were a lot to choose from. And unlike the regular beds, the MFT doesn't limit those choices at all. Other types of bed caps or toppers are a problem though, as you said. But since I have no interest in those it isn't a problem for me.
If you think you'll miss the little bit of bed space in front of, on top of, and behind the wheel wells then don't get the rambox option. I just think too many people don't realize just how little they will miss not having that bed space. I was one of those people until I had access to one. It totally changed my mind about that. I like being a part of a small group of people who are rambox owners. Kind of makes it an exclusive club.
I don't understand why they even make a v8 equipped truck with a 23 gallon tank. The 26 gallon tank on the 4th gens was bad enough. The only thing I can guess is they were thinking the etorque would improve fuel economy enough to make up for the smaller fuel tank. I'm surprised that my mileage is as bad as it seems to be. At this point I've just resigned myself to accept the mileage for what it is and enjoy the truck. It really is a great vehicle.