Nero
Mmmm...cookies
I don't think so.
While Hideo definatley played a major part in the MGS storyline, it was never 100% his work alone, there were supporting writers and developers working alongside him. Even in MGS4, he was willing to listen to his staff during the development.
For example, in the original plot, Snake & Otacon were to turn themselves in, and then executed. But it was changed after the response he got from his supporting staff.
I'm fairly sure Kojima will be able to "pass the torch" quite well, and have his teammates step up and take the lead.
Well, that's what I'm hoping anyway.
The execution idea imo would of been a great end to the series, oh well.