Bill Gates and new CEO Satya Nadella initially opposed the Nokia deal, as did the departing Tony Bates. Nadella later relented; Bates didn't. Though Ballmer mostly got his way - the final deal didn't include the mapping unit - Bloomberg states his antics were "the last straw" for some directors.
The news service also states Alan Mulally's ego "got in the way" of his CEO candidacy. Though the Ford CEO expressed interest in running Microsoft, he refused to formally interview.
With Gates and other directors deciding a CEO with a tech background was needed, and many candidates (inc. Mulally) worried about Gates/Ballmer's continued influence, Nadella eventually got the job.
During a recent talk, Ballmer said his biggest mobile regret is that Microsoft didn't offer integrated hardware/software solutions earlier. The remarks come shortly after Google, provider of the world's dominant mobile OS in terms of unit share, struck a deal to sell its phone unit.