I agree the best "whoever owns Amiga now" could do would be to sell cases (not being arrogant now). Containing misc hardware that works like an Amiga.
As far as that hardware is concerned, my dream would be 680x0+chipset remade 100% compatible, even if that is 68000+OCS (read: A1000). Maybe not 100%, but it needs to be "more accurate than WinUAE", so very close. Whatever modes are added on from there are a plus, and there could be an "n times" accelerated option, etc. The rest of the hardware (ports, compatibility with real-Amiga expansion) are irrelevant now.
But when non-Amiga things like 68000 emulation with another CPU running a non C= OS and graphics cards with pixelbuffers the chipset can't use get involved you lose what Amiga is. It's no longer an Amiga, no point for me.
Simplest possible "Amiga core", 100%. I would be extremely happy and content with that. Minimig really isn't that shabby, even if you'd want to be able to dev properly on it for it to be a replacement (compatibility, full install of whatever WB version you want, support of the Assembler etc of your choice etc.)