#3D-RISC
Nothing about RISC or AAA will inherently break all software. Most software
that works with graphics cards today would probably have worked fine under AAA.
Dumping a RISC into an Amiga and running a full 040 emulator on it wouldn't
break much of anything, but there wouldn't be any point (an 060 would be
faster).
To get the benefits of RISC, you've got to port apps to native RISC. If you've
got to do that AND adopt to a new chipset which isn't Amiga-like, what's the
point? I mean, you might as well fix all the yucky DOS stuff we've inhereted,
add VM and protected memory, change the exec message passing scheme to suit
that (and to be networkable), etc.
At this point, there is no reason to call it an Amiga or to think that it is
any easier to port Amiga software to it than any other software. No reason
you'd need to own any of the old Commodore.
Of course, I'd be all for working on such a machine. Anyone got a billion or
two lying around unused?