My 2 cents -- I just don't get it.
Retro is cool because it's retro. When I use the Amiga, I'm "reliving" what it was like to compute back "in the good 'ol days". A modern reinterpretation of Amiga OS and hardware gives me nothing that Windows, Mac OS, or Ubuntu on x86-64 hardware doesn't already provide.
When the Amiga came out, it was truly revolutionary and special as a home computer. The graphics, the sound, the pre-emptive multitasking OS. All of that is standard (AND MORE) today.
So if you're going to make a modern Amiga and recapture imagination, it needs to be truly novel, not just some PPC pumped-up PC from 2005. Otherwise, I'll stick with my MacBook Pro for day-to-day computing, and my classic Amiga for weekend retro benders.