Well, I'm not fan of PPC... I think it is bloated and feels like a compromise design. MIPS and ARM are much more beautiful IMHO. I know virtually nothing about PA-RISC, but I do know that Hombre planned to use several small PA-RISC cores as standard :-)
Hombre might have saved Commodore, but it would just have likely spelled the end for the Amiga... Which would have been relegated to the C64 position in the product line up.
Obviously I don't agree with you about the PPC.
And until recently ARM has been under powered.
MIPS holds no interest for me.
And PA-RISC is a dead issue. Although Commodore might have helped it succeed.
Hombre could have helped AmigaOS carry on if they'd followed through with that part of the plan.
As it is, the NG OS' resemble that idea.