He's kept the ship afloat and is good at maximizing profits from MS's traditional businesses. The problem is that Ballmer isn't the person you need in a transitional phase for a company.
Remember when they haven't shipped a web browser in Windows 95 and then they turned around and produced a kickass browser that killed Netscape Navigator? Or how MS Word took marketshare from WordPerfect like taking candy from a baby? Or how Win 95 won against IBM's OS/2, even though OS/2 was also binary compatible with DOS and Win3.11?
There's no question Gates was as much of a skilled tactician more than a coder (which he was great at when he did it) but, while I'm sure he still loves MS, he is a man in the real world looking for a cause to drive him. MS is in the past.
I can't blame him. A good woman changes you and that's what Melinda did.