You can't emulate everything you can do in the PC in a console.
Can't emulate auction houses, real money auction houses, fast paced hack&slash with proper targeting.
Try to imagine playing Diablo 3 on the hardest setting against a horde of monsters.
Or just try to imagine Diablo 3 PvP on a console.
And for people saying about ages.
Roflbbqlolcopter - SC2 Community is proven to have around 18 to 24 years and it's followed by 24 to 35 years old users and then is the below 18 guys.
So don't even compare blizzard games with anything else. Diablo is even older than starcraft, for sure most of the players in Diablo 3 will be between 18 & 24 years old.
If blizzard plans to go to consoles, for sure it wont be in the fashion of the classic games.
It will be a totally diferent style, like that FPS that they tried to do of Starcraft universe and I hope this time they don't uber fail again