I see a couple of different things here:
1: One of the above posters is right, the PS3 is somehow like a modern Amiga, it would just need its own OS. Lots of custom stuff in there, and using the CELL chip instead of a generic x86 or windows approach, and it’s a powerhouse leading in front of the other consoles (just my opinion

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Imagine Commodore would be still around and not acting as retarded as in the late eighties/early nineties, this could be how a modern Amiga would look like.
2: The OS way: If no dedicated hardware is around, I would go the x86 route. Like the rest of the possibilities, it doesn’t hold much future, because except of a few nostalgic geezers like us, nobody will give up their Windows/Linux/MacOs operating systems for Amiga Os in any form. There is simply not enough power behind the Amiga anymore.
3: Natami. If this is real, and I am not yet convinced that this will ever see the light of the day in any form (I believe they got their “Super Aga” running, but getting a 68040 running on the same FPGA with even higher speeds than the originals sounds a little bit farfetched to me). Well if this is real indeed, I see many chances. You have the fraction of oldschoolers, who want to play their old games and use their old software, but you can also get the people along, who want to use their Amiga for more modern uses, browsing the web in a convenient way for instance. Plus a couple of nerds (like me) would maybe be interested to develop something new for this.
Natami and AROS together sound like a dream come true to me, and the best thing with this is, you have people from the community working on the future of the Amiga.