Ballmer said the "number-one thing" that's changed at the company is the way he, Ozzie and Mundie interact as a team to make technology decisions. "The way the three of us accomplish, let me call it the job at the center of technology leadership, is certainly different than the way Bill did," he said.

Gates, on the other hand, had more of the final say himself in technical decisions, Ballmer said.

"He was the founder. I might have been the CEO, but he was 'the Bill,'" he said. "There was no question that if Bill thought something should be done ... he actually didn't give orders much, but if he thought something should be done, you knew life would be intense if you didn't agree. Let me say it that way."

Still, he said, given the choice, Ballmer and his colleagues would be happy to have Gates back.

"We miss Bill," he said. "I mean, if you gave sort of the average senior technical person at Microsoft a vote, 'Bill back, Bill not back,' they'd probably say, 'Yeah, it'd be great to have Bill back.' On the other hand, Bill's doing something important that everybody values, and I think everybody relishes the opportunity to grow and take more responsibility."