Sounds to me like this is just a matter of what you're used to. From my experience, OS X's UI is the last thing anyone would want if they weren't used to it. The window management is pretty damn horrible. OTOH, Linux has a variety of window managers with many innovative paradigms.Your experience does not match mine but thank you for trivializing mine by assuming that it's just what I'm used to. Never mind that I come from a Windows and Linux background, to OS X about three years ago, right?
I find the OS X window model appealing (though not without its warts) and its gesture support fantastic. Mission Control maps far better to the way that I think about multiple desktops than GNOME's or KDE's--and I compare to those and not your "innovative window managers" because I've been there, I've done that, and I have determined that they're not for me. I have been down the tiling window manager road and I find it demanding of micromanagement; it does not map to how I think or work and I have no interest in contorting to fit it. Likewise, I have no interest in putting up with sharp bits and pointy edges in Unity or GNOME 3 or KDE 4 (I've been there, too, and reject the T-shirt).
If you want discrete graphics, that is available in other models, such as the T series, IIRC. However, for anything other than gaming or video editing, integrated graphics really is enough.
The rMBP is not my only computer, but, yes, I want to be able to play games on it when I'm traveling. The rMBP is really good at it (I generally just play through Parallels, I don't bother to reboot). The T-series Lenovos are massive, heavy, lack Retina displays, and aren't nearly as aesthetically pleasing as the Carbon X1 is. Would never buy.
The only thing missing is retina support, but you have the advantage of a lighter and thinner laptop than the MBP.
"Except for the most important thing, you get some of the things." Sure, I'm being flip there, but it's not unserious: for my money, retina support is just not optional anymore. People say they can't go back after using a retina display because it's true. For me, the difference is that stark. The 3x 21" 1080p panels on my desktop feel distractingly blurry and they make me irritable to work on for long periods of time. (Most disappointing thing to me is that the DisplayPort outputs on the rMBP can't output 4K, but 2560x1600 displays look okay when put far enough back on my desk.)