On size/weight, I agree that a lot of gamer/desktop-replacement machines are much too large and heavy to be portable, battery life suffers too much, and often they get too hot to be used anywhere other than a proper desk or table. My W530 is a 15.6" 16x9 screen, around 1.25" thick, and around 6lbs with the larger-capacity battery -- its really at the outer limits of what I consider portable, and I would have preferred, if possible, to have the same machine in a 14" and slightly slimmer package. I would have gladly paid a few hundred more for that. Alas, no smaller Thinkpad met the specs, and other vendors might have been close, but then I'd have to give up the dock or other thinkpad features that I like. You can say you won't mind carrying a huge laptop around, but it will affect how much you get out of it -- a portable machine isn't so portable if its inconvenient or burdensome to take with you, even if its possible.
People that have those massive, 17" (or 19" !!!) 12lb Sagers with 3 hard disks in RAID, and 154Whr batteries that buy them 94 minutes of run-time aren't moving them around a whole lot. Sure, from their desk to the lan-party on the weekends -- or maybe from their work-desk to a graphics conference a couple times a year, but not back and forth to work or school every day, or to the coffee shop, or even to the patio or couch, probably. I really can't imagine owning a laptop 17" or larger. To each his own, I guess, but I think I'd end up feeling like I had bought a lie.
Another note on resolution with respect to screen size -- I've got 1080p at 15.6", and its actually a pretty darn comfortable balance of screen area to resolution. 1080p at 13.3" begins to border on the limits of practical comfort. I think 1080p at 14" would be an ideal balance of size, resolution, and bulk of the machine itself. Retina-style super-high-resolution displays are really nice to look at, and for many apps (even writing code), the sharper detail is great and helps readability of text even -- but with pixels so small, 3200x1800 on a ~15" screen isn't the same deal as 3200x1800 on a larger 24"-32" display -- the former increases sharpness, but doesn't give you more usable working area in the way that the latter does. Also, full-screen apps like games aren't going to run at those native resolutions, and that means halving them for the best picture -- 1600x900 in this example. That might not be where you want to play your games. Most retina-style displays until now have been these fairly odd-ball resolutions, but real 4K (quadHD) 3840x2160 panels are just now finding there way into laptops, which is nice because half resolution is 1080p.