1. Include the start menu and the start button back. There should be a dedicated switch-to-Metro button either in the start menu or in the task bar in the near of the clock. Besides when I'm at work where we have Windows 7, I miss Metro a lot. Of course, my Start menu hasn't gotten used in a long time anyway. Between the task bar, search, and Bins, Metro is a natural progression to not having to hunt for things.
No. Disgruntled and stubborn IT "experts" would take it upon themselves to project their views on all of their customers, the very people who Metro helps the most.
2. Let the desktop programs be the default for files you open in the desktop. Shouldn't be hard, since WMP and friends are still shipping with Win 8.
Meh. The Metro versions of apps tend to start a lot faster than the desktop versions so I haven't seen the need. Also, see response 1.
3. Add a Boot-to-desktop option in the control panel.
spivonious said it, how else can you get a view of all of your status information without starting six different programs? Also, see response 1.
4. Desktop programs shouldn't be visible in the start screen at all.
No, that would be confusing and frustrating to not be able to find things. These changes you require actually bring less consistency and discoverability to the system.
These changes are trivial to implement, and with Microsoft's man power, they could be included within a week.
If you believe this, then please don't ever become a developer.