Some thoughts on various points:
1.
Windows 3.0/3.1 applications could access hardware directly (Windows 9x/Me
apps could as well, but it was less common because NT compatibility was more
important). Even Windows XP cannot run all Win16 applications (or those
certain Win32 apps that did funky things); full native compatibility is a
fairly ludicrous goal. Probably better for users to just run Windows 3.x/95
when necessary in DOSbox or QEMU.
2.
Full DOS compatibility is probably even more complex than full Win16
compatibility. Besides, DOSbox already works wonderfully :)
5.
Good idea. Windows NT desperately needs something that has been easy as pie
since forever on Unix.
6. MythTV?
7.
Tons of work would be needed for little benefit (btw, 386 and 486 are 32-bit
processors). If needing to use these machines, it's probably a better idea to
use FreeDOS. Also, you seem to be confusing Windows 95 as being purely
16-bit, it is not.