Develop a desktop environment that genuinely feels and functions like a fully-featured Amiga environment, and then you'll only be left with all of the underlying structure that feels absolutely nothing like it and also it doesn't run any Amiga software. Yeah, sounds like a plan.
I guess this is one of those nebulous "what makes it an amiga" things.
On my end, I don't really care what this or that folder is called, what the file system happens to be called or whether the kernel does this or that.
The user interface and experience on the other hand, is what you engage with every moment you use the machine.
As far as amiga applications, port or emulate. Not really different from the OS4 people. Or build in some sort of compatibility layer like the Mac people did with their switch to Intel. Who knows?
Except for the part where Amithlon was nothing at all like Linux, sure.
It runs on a linux kernel, so I'd say it is entirely like linux. In fact, Im not sure if we're talking about two different things here?
"Linux" is the kernel. People glue all sorts of stuff on top of that, to make the typical desktop experience you get from the various distro's but those are specific examples, not the only possible answer.