Sounds bad idea to me. You said it would be Rolls Royce of the consoles and it probably would sells as much or less. If it would be $600 or even $500 and people would know there would be better console coming in couple of years then very few would buy it. Consumers are suprisingly patient and can easily wait couple of years. Even those wanting best equipment would just skip the console for next generation console (this has happened before). They can't even mention forward compability in their marketing because that would reveal that a better next generation console is coming soon. And that would kill sales totally.
Mandatory installs, loading times etc are not the reason why PS3 and 360 haven't sold better and they are a non-issue for majority. Most people don't have a big problem with loading times. And because all games are on cheaper consoles there in no reason to buy overpriced consoles to play the same games.