@uncharted
No, it's that I really am not the ideal person to explain OS design theory to anyone. While I understand it, explaining it I am not very good at. But let me try.
The fundimental problem I see here is that you're thinking too much in the AmigaOS mindset on how an OS has to run. The comments about not being able to use Quark from within the ABox demonstrated this to me. Of *COURSE* apps within the ABox can use Quark. Otherwise, as Quark is the kernel of the system, nothing would run! Can you directly access Quark, no, because it exists outside of the ABox, but you can use it. How, you might ask? Simple, you have a window into the lower-end of the system, namely the HAL and reimplimented exec.library. The new functions that can be implimented inside of the ABox without breaking the API's can be access this way, through this window. That way, since there is a barrier, you cannot kill the whole system with some dumb random crash. It is the only proven method of ensuring a stable environment without destroying compatability. It is how MacOS, OS/2, WinNT/2k/XP all do it.
In a way, AmigaOS's own multitasking strength is now it's weakness. Compare to Atari's TOS, single-tasking OS. AmigaOS, one cannot add MP, VM, etc without breaking the API's and causing apps to not run because the apps are engineered to look for other applications, libraries, modules, datatypes, etc and just fetch them out of memory directly. A full MP environment requires a program to ask the OS for these components, rather than just do it on their own. This means, if one were to add full MP, one would break this ability, thereby not allowing the application to run at all. Atari's TOS, by comparison, is little more than DOS, a single-tasking, no-library OS. WYSIWYG. This allowed some smart fellas to create the MiNT kernel, which creates a virtual-machine for each application, allowing one to run many TOS apps simultaneously, all with full MP. However, this turns into Windows, with monolithic apps, and is very ugly in the long term. None of the sharing and beauty of AmigaOS.
man, that was one long rant. But did any of that make sence to you?