akuma - Im not sure about assassin's creed, but for COD4, yes, it would have even if it didn't push the technical envelope. It was a refreshing setting to the genre, one sensitive to current times and matters in the mideast. it touched the american people who are gung ho on taking out terrorists, etc, which is what pushed a good chunk of the crowd that normally doesn't buy such games, the big selling point for COD4 was the excellent online play. I think that people would have been driven to the game without the shiny graphics due to the excellent gameplay.
As for worlds rendered in real time, I've already burnt myself out on MMORPGs that offered the same, so its not exactly new technology for me, but that's the case with all consoles vs the PC. Playing a new console game is like playing a new game with 3+yr old pc technology. Thus why I do my share of PC gaming. Right now Im playing games with quality you'll find on the NEXT gen consoles.