I agree with much of what you stated, however I think I do detect a slight lack of objectivity on your behalf, which may be contributing to a more negative view than you might otherwise have. For example this:
Sure, once you get used to it, and spend weeks tricking it out like turning off all the useless full screen apps and installing useful ones, it may be of a similar productivity.
On my work PC metro apps are completely useless. Just like you I don't want metro apps to interfere. Uninstalling the few annoying metro apps (PDF viewer, Picture viewer, and one or two others), removing some of the metro icons from the start screen, and setting IE to always open on the desktop takes me at most 10 minutes. I don't mind exaggerations here and there to get a point across, but claiming this takes "
weeks" is definitely taking things too far. Just configuring the start screen (or the start menu in W7 for that matter) takes notably longer than removing metro apps from my desktop PC. Once you do that, W8 is no different to use than a normal W7 desktop!
The start screen may differ visually, but structurally it is identical. The start screen is just a larger area for "pinning" icons. This is the exact same thing as "pin to start menu" in W7. Click the arrow and you will see exactly the same thing we previously found in the start menu after clicking "all programs". It's the exact same thing, and even requires the same amount of clicks. Again... the same.
It is simply not a desktop OS.
This is where I think you and many others went off course. Because the usage paradigm of W8 can be fundamentally the same, the W8 OS is
just as much a desktop OS as W7 ever was! In fact, I think it is objectively better as a desktop OS.
On the other hand, I think everyone agrees that MS completely screwed up the W8 launch. You mentioned most of it. I think MS is still screwing up by delivering a very poorly configured W8 out of the box. They probably should have set it up so the start menu is the only difference and let people explore the metro apps on their own, at their own pace, if they so choose. Forcing people into metro apps, when the new start screen was already more than most could handle, was a bad idea. The lack of information on where Windows is headed (some still think metro is destined to eventually replace the desktop), and the lack of video tutorials and interactive help explaining why the start screen is the better start menu was the final blow. Most of that has still not notably improved.