There is some valid points here, but 1520 is a kind of "pioneer" and driving the development of Operative System and Apps, in many aspects.
WP has just added 1920 x 1200 support, but they didn't do much else to take advantage of this huge real state. The WP development team seams to have been taken by surprise, but the real evolution will come when App-developers start taking advantage of this new big and high-resolution screens. It's just a matter of time, soon both WP and Apps will be adjusted/redesigned for high-res screens, and of course the future holds 2k and even 4k screens.
The same is true about the new powerful Snapdragon 800 SoC. It has enough juice to run a full blown Windows 8.1, but the WP development team seams to be hanging behind, again. The WP 9.0 will probably use one unified Operative System for Phone, Tablet and Desktop. But In case, it couldn't be relisted without these kind of powerful SoCs.
The hardware specification of 1520 is too good for it's time actually, but it's driving the development of Operative System and Apps to catch up. All technology pioneers face similar challenges for a period of times..