>>"TL;DR In short, you are saying"
Got to appreciate someone who starts a post by saying mine was too long so they didn't read it, and then posts an incorrect synopsis of what I wrote.
While TL;DR might have been a bit glib, the point is you made a huge rant on telling us how we should be liking Win 8. We are just not holding correctly, perhaps?
In fact you have made one critical point yourself:
"...the very basic fact that you can get the Start Screen from clicking in the lower left - something that Windows tells you the first time you start up"
What if you did not go through the tutorial because it was someone else's PC? Or life was just too short?
Discoverability. The principle of least surprise.
Win 8's interface violates them both big-time. Now that is not to say others do not share some of the same stupidity of this approach (Ubuntu's Unity, a lot of Android, some of iOS) but the basic fact remains the same: What was an acceptable user interface for XP (more so if you chose "classic" a la Win2000) has become an exercise in sucking donkey balls. Actions are non-obvious, you have to learn things (hello command line, I love you!), and you are trying to do something and you get the metro screen slapped in your face due to some non-obvious track-pad gesture.
Choice. Why not? With XP you could revert to Win2000 if you preferred, which I did. Why are we now forced to use metro?
That is a rhetorical question, as the answer is well known and explains why most are unhappy. We are forced to suffer so MS hopes to get developers, developers, developers for an interface few wanted.