Why would Microsoft remove the beautiful Aero Glass effect and replace it with flat colors and cheesy translucency?

Beauty is in the eye of the beholder . . .

This is all a discussion about aesthetics.  It may be disguised as a choice discussion, but truly, it is aesthetics.  

Other products (in all worlds of products) change look/feel and do not give options built-in to go back to the old look/feel.  The choice of using/not using/finding an acceptable work-around/using a different product still exists.

Those who make the products choose the options available and none have satisfied 100% of possible customers nor will they likely ever do so.

Personally, I actually prefer Windows 8 over 10 in terms of looks. This is the age of VR, and regardless of what device you use, VR is the future. VR needs to look realistic, right? Now, Metro theme can be cool if done right. But the Windows 7 aero is what's cool to me! It's like a silver spaceship - and not one from the 90s. It's pristine, light, nice...

Ok, the problem with Aero is that is only works with backgrounds that are blue, and a very saturated blue for that. I tried to look for some "Aero compatible" wallpaper, but the only one that works with Aero is the boring base desktop wallpaper. (I need photoshop! I can get rid of the Microsoft logo and add a super cool spaceship on that wallpaper!). When Aero is paired with any other color, specifically warm colors or gritty colors that most hardcore gamers like and use (yeah.) it becomes ugly and distracting. And I do know that 3d elements aren't always good - look at this garbage:

https://www.imperica.com/images/stories/photo/0194/1001/au-al-0194-1001-04.png

The thing I hate about metro is well, more links here:

http://blog.usabilla.com/wp-content/uploads/Mark-Boulton-Design.png

See, it's too featureless. Too grey, no color.

When you said it looks like flash gordon serials, it might have been because of your wallpaper, or perhaps you monitor is weak. The best way to do 3d elements (in my opinion) are like what I said. Like the interior of a silver spaceship. In houses that look like this (CoD Black Ops 3 spoiler!):

http://i.imgur.com/kwlXtVh.jpg

Aero/aqua/whatever is best, but for these kind homes:

https://s-media-cache-ak0.pinimg.com/736x/d0/59/9a/d0599ab57ea81b6bb6746ea1bd697233.jpg

the place screams, METRO! 

We can agree on one thing though. Beautiful UI should be so pretty, we don't even notice it. And if you like Merto, that's great. But we feel like we're being replaced and pushed out, you get it? Metro should have been an alternative to Aero, not a replacement. See what you think of this.

I agree with the Windows XP though. Back then, Apple was so much better than Windows, I don't know how XP got off the ground.  I'm not saying XP's bad, just that back then, Apple was sooooooo much better.

Just how is metro futuristic?

This is an aero styled future city: http://www.futureofcities.ox.ac.uk/media/2014/04/Future-City-1300x728-600x270.jpg

ie, Dubai is like that.

Metro, despite what Bill says, seems an awful lot like the 50's theme for little children... or a cartoon...

I'm not saying one is better than another truly, just stating facts. And no, one size does not fit all.

You know, people said the same thing about Windows XP with its bright colors back in the day.

We'll just have to agree to disagree. Personally, I consider the streamlined, easy to use design of the Screen far nicer than the convoluted Menu.  To me, Aero Glass is right out of the old Flash Gordon serials - total zeerust! :-) But what I really was saying was futuristic was the ability to have both UIs and program styles in one system side by side or one at at time as the user prefers - it's the functionality and flexibility that makes it "futuristic" rather than strictly the looks.

Frankly, a big part of my acceptance of Metro comes from my loathing of the Start Menu - hated it in 1995, hate it to this day. So a big part of my liking it is simply the fact that it wasn't the Menu. ;-)

And as for Aero specifically, I liked the actual functional elements - Aero Peek, that sort of thing. The things that actually could contribute to productivity, much of which is still present. The translucency effect I always found cheesy and distracting. It was cute, but added nothing of value to me. Which isn't to say it shouldn't be included - I just don't feel the need for its return that you do. Honestly, what I want back in 10 is the Start Screen.