David Sokol is CEO of MidAmerican Energy. According to Barrons, Buffett has no apparent qualms about Sokol. In Berkshire's 2002 annual report, Buffet wrote that Sokol and his top deputy, Greg Abel, are "huge assets for Berkshire. They are deal-makers and they are managers. Berkshire stands ready to inject massive amounts of money into (MidAmerican) - and it will be fun to watch how far Dave and Greg can take the business."
It will take someone with a big ego to follow Buffett, and Sokol has that. He also has another attribute that might appeal to Buffett. He was born and raised in Omaha and educated at the University of Nebraska.
Buffett is looking for more acquisitions in energy!