thats possible.. I dont know about what it takes to make a system reverse compatible.. but I do know that just having the feature limits the system power (coding and chips on the circuit board being used for the old games, where they could be used to further the architecture for the new technology).
if they did either total backwards compat or selective compat.. I'd hope they'd do what sony had, where you can add more graphics to the old games.. and even have a faster reading speed and so on 😄
hehe.. hope the games have a very different feel from their E3 demo counterparts.. cuz the differences from xbox to 360 were fairly subtle in terms of design and approach.. i.e. dead or alive looked the same, but with higher rez stuff attatched.. I was hope it would have somewhat of a different control scheme