I'm finding my conservative, common sense approach in general is increasingly unwelcome here on FR. Guess I've been around too long. Not many of us Class of '98 left on here...
Silliness aside, you are spot on with your assessment of Win8, but I disagree that Win7 was the “prettier” OS. I think Win8 wins across many measures for aesthetics.
Aesthetics are more personal preference in nature than "fact based." It's like art. Some people love Picasso, people like me can't stand it. (Since my office window looks out on Dirksen Federal Plaza in downtown Chicago --- the murder capaital of the world --- where a huge Picasso is housed, I speak from some experience here.)
Win7 had the “bubble” feel to it. Win8 has gone back to the “2D” look and feel where flat and edgy wins. Full disclosure, I work in Win8.1 and Server 2012 R2 all day, every day, so I may be biased but I’m also experienced.
Disclaimer: I have a slight vision impairment so I cannot speak to the "bubble" effect you see. I see a more "flat" and "opaque" or "transparent" effect in Windows 7. Windows 8's flat/pastel colored tile effects aren't visually appealing to me. I frankly never understood why Microsoft introduced two completely conflicting UI paradigms in Windows 8. Especially when one of those paradigms was completely contradictory to the concept of windowed applications (the Metro UI.)
I can answer this for you. I'm a Microsoft Certified Professional and speak with MS types quite a bit. Microsoft wanted a "fresh look" for Server 2012/Win 8 and opted for the flat look that is found almost everywhere on popular websites now. FoxNews, WeatherChannel, Yahoo, etc. have hopped on the "flat" or "2D" bandwagon, and Apple, with their release of the latest iOS revision did the same. Far be it for Microsoft to be left behind, so they did the same.
I can completely understand your side now that you mentioned the vision impairment. Microsoft tries to accommodate everyone, but I've noticed as well that oftentimes their default choices are appalling.
The Modern (nee Metro) interface was Microsoft's attempt at changing how people use their desktops. Once people realized they could just go to their old-school desktop, it's stopped being a big deal. I personally love how much more power you have by right-clicking on the Start button whereas before you had to right-click 'My Computer' > Manage, etc. For Windows "power users," Win8 is a great step.