Hmm... finding this thread a wee bit confusing...
It's posted under "Amiga Hardware Issues & Discusions" but it mainly seems to be about MorphOS running on Macs, I admit I know very little about MorphOS but I'm kinda confused about where the Amiga fits into all of this or has A.org been taken over by a Mac forum...
MorphOS basically *is* (an) AmigaOS. It started a bit more than 10 years ago to write an OS that is fully OS3.x compatible, shares the same API and logic to use.
There is exec, intuition, dos, mui and all that stuff under the hood. The disklayout is the same as under OS3.x (c, s, devs, libs, prefs, utilities, tools, classes, locale), the RAM disk works the same, DOS shares the same commands and syntax. It is directly comaptible to non custom chip banging 68k software, as well as PowerUp software and WarpOS software.
It is written by many of those folks who actively kept Amiga alive when noone else was there in the late 90ies. The MorphOS-Team was in negotiation with Amiga Inc to make MorphOS the official AmigaOS4 but the conditions were unacceptable, so Hyperion later took this. MorphOS suported initially the P5 CyberstormPPC and BlizzardPPC (support for these cards ceased with the 2.0 release), then the various Pegasos computers and the Efika5200B.
Recently MorphOS happen to support some Apple PowerPC gear. Maybe in future MorphOS will shift the supported ISA, but not too soon.
Is that Amiga enough?