Maldacena's strings 2011 talk is about the "wavefunction of the universe". You have to be drunk to use the term, but you need to lose your marbles to give a complete talk about it.
Seiberg's talk is as wrong and narcissistic as all the talks he gave since the 1990s. He lost his marbles already back then. His missionary zeal, combined with the nonsense he talks about, is distressing.
Witten's talk on maximally supersymmetric Yang-Mills theories is not about physics at all, but about knots. Witten shows again that he left physics for mathematics.
David Gross still thinks he is a great physicist; it seems that nobody told him that repeating nonsense is not the way to become one. His opening address is really bad and self-centered. He still hopes that supersymmetry will be discovered at the LHC. We will see.
It really seems that the main figures of string theory have lost their marbles even more than the less well known ones.