While on the surface it is very easy to understand the Balmer hate because he comes off as loud, slow, annoying, and uninformed. And yet he has been in charge of MS for quite a while now, and has not only managed to not sink the ship, but actually grow it.
So while my initial reaction to balmer being placed in charge makes me think that XB1 will now just be Halo and sports games, I have to step back and realize that while I do not like him, he has made some great decisions in other departments so this may not be so bad.
I still dobut that we will see cross-platform capabilities between XB1 and Win8 PCs like we should this generation... but who knows. Maybe something good will happen.
Vista was under his wing (no need to say more on that), and Windows 8 has far too much bad PR (regardless of my opinion on it). Windows phones in the market are still...a failure, and so are the tablets, both with a very slow adoption rate. On top of all of that, there are some economists that have asked him to kindly step down; also, when a head of a company is hated, for whatever reason that may be, people just stay away from their products or are less inclined to get future products from said.
All in all, I wouldn't call him successful. The only real success I know of under his leadership was Windows 7. I'm not sure how involved he was in the Xbox 360 later on as well, but that's mixed in itself. With sales being off the charts, yeah that's impressive. But with the fiascoes they had with it, like the as high as 70% hardware failure rate, I don't know what to call it.