Look, the Amiga will never compete with today's PCs and MACs. That's a fact. They've been out of it too long and they wouldn't be able to produce hardware and an OS that could run the range of software that I use.
However...if they got together with some game publishers and produced a machine that could run games of the same type as we were used to in the old days, but slightly better spec (in terms of gfx and sound) then I would be interested.
But it would have to be backwards compatible so I could ditch my A4000T. Maybe it would have a Minimig-type daughter board with an 030 and 16mb RAM for those classic games.
I guess what I would go for is a machine that could give us games like UFO, Worms, Wings etc. That's the flavour I would be going for. Fancy FPS and online multiplayer games are for PCs. Amiga won't do those better.
But yes, make a new Worms, Wings II, Superfrog II etc and the people will buy those machines because all Amiga has to trade on is nostalgia and the 'classic' feel of the games. It probably wouldn't take much to update many of our favourite games and add levels/gameplay to them.