A lot of the good things Microsoft has (deservedly) received praise for recently under Nadella were started under Ballmer's tenure. Yes, he is not personally responsible for everything that goes on at the company, but it's important to keep that in mind.
[0] While the decision was reversed on appeal, Microsoft was literally ordered by the courts to split itself into separate companies: https://en.wikipedia.org/wiki/United_States_v._Microsoft_Cor...
[1] http://arstechnica.com/information-technology/2011/04/depart...
[2] Incidentally, the Surface, which now appears to be Microsoft's attempt to clean up the wild west that OEMs have created, was announced right at the end of the DOJ's oversight. I cannot believe that this is a coincidence.