Much of the attraction of the Amiga (and the Atari ST) from that time, as far as I remember, was the 'step-up' in terms of the quality of the graphics and the games, when most people were rocking 8bit micros like the C64 or Amstrad.

In terms of what you could do software-wise, I think we can forget about the mainstream games industry. Same with the mainstream graphics industry (for the reason we have no Adobe Creative Studio for Linux).

What would interest me would be a killer OS with an active ecosystem supporting more indie-style products like Firefox, Sketch (https://designcode.io/sketch), Sublime Text, Atom etc, as well as indie games like Hotline Miami.

Start 'small' and see where it goes kind of thing.

I, for one, would be very interested in something like this.