I think it is way to far in the console's life to even consider anything like what you suggest. Micosoft did all that when the x360 was relatively "young", giving developers time to create games for diskless and HDD capable x360s.
Apart from add-ons any new major revisions is pretty pointless IMO when the console is half way through it's life.
As superchunk said concentrate on reducing cost of the current console and don't waste money on redeveloping or re-arranging it's hardware.
To be honest I think if Sony did what you suggested they would probably loose marketshare than gain it.
One of the strong selling points of the PS3 is that online gaming is free and you can drop your own HDD in it.
If they just copied MS and did as you said a new gamer looking for a console to get into gaming might as well buy the x360 because the PS3 offers no other advantages...apart from BR.
