Here's the thing about PowerPC and MorphOS/AmigaOS: it was tried. And tried. And tried. We aren't relying on any guesses or opinions here.
The original Pegasos fell foul of a northbridge with cache coherency bugs and the fix was expensive and hammered the system's speed. The original AmigaONEs did not fix the issue and much of the board's functionality was replaced by extra cards to avoid triggering them. The hardware had unadvertised bugs.
The Efika was almost useless for desktop because it's SoC had never been designed for it. The hardware was insufficient for intended use.
The Pegasos-2, while faster in every way than the Peg-1, was on paper inferior in several ways because the Marvell just wasn't as advanced as the Articia. The hardware was limited.
The X1000 ran out of the supply of PA6Ts to continue the line, simply because they weren't available any more - and even when they were, they were too expensive.
More recently, the Tabor has been endlessly delayed because every time the board is finalised, some component or another is no longer available.
PowerPC, as a direction for MorphOS, failed because of these reasons: price, availability, power and robustness. It would seem to me that if you want to choose a new CPU family and not fall foul of this again, then you should:
* avoid proprietary hardware * avoid non-mainstream hardware * use specifically designed desktop or notebook hardware * Use only well-tested designs
Right now, that means x64. The only way this will change if desktop ARM flourishes and diversifies... and isn't just controlled by Google.
