Going from 1920x1080 (16:9) to 1920x1200 (16:10) is better because you get more vertical estate. But you seem to suggest that 1728x1080 (16:10) is also better. Aspect ratio does not automatically make a resolution better lol.
Aspect ratio has nothing to do with resolution. 16:10 is much closer to the golden ratio, which allows to split the screen vertically in half and give two vertical screens with roughly the same ratio again.
16:10 has proportionally more vertical screen space, which is much more important given that most our documents/sources are oriented vertically. Not to mention wasted vertical space that cannot be removed (toolbars/menus/etc). Having more horizontal space is useless if you're mostly working/viewing with a single document at a time. If you physically rotate the screen, the 10:16 ratio is again better at fitting a piece of a A4 paper.
The 16:9 ratio was driven by consumer demand, but no professional user I ever met liked it for working. There's a lot of unused horizontal space in just about every scenario. I personally stuck on 4:3 as long as I could, then switched to 16:10. Admittedly, 16:10 is "good enough" for me that I wouldn't necessarily go back to 4:3 now.
