Worst case is "Xbox allies"?.
The worst case is that a massive significant part of PC gaming is under MS control, and that's something I wouldn't want at all. It was bad enough when they tried to put down lock & key with GFWL, it'd be 10x worse if they straight up owned Valve/Steam, because I know they are very much into turning everything they buy towards their Xbox ecosystem, and well, I don't want that, because I've never been a big fan of console ecosystems, because they do not allow for much freedom in the first place.
I don't want some console folk desiring a PC company be bought out for their petty, completely insignificant console wars.
Don't decide what's best and what's worst for me, or other PC gamers please, because your dreams are not shared by me, nor everyone.
You better prepare yourself, they will buy valve my guy.