You are aware that Pox is not legal in 1.X, not since November, at least. While Balance is powerful, it IS restricted and not worth splashing another color for. W/B Pox can work, but MonoB is better in a competive meta, infact my deck SMOKES Keeper and almost all control decks.
Quote Regarding the Powder Keg, how do you plan to use them ? Do you target Mox (are you playing in an environment with a fair % of power card ?). If not, Keg are good at providing card advantage and are typically useful against cheap creature rush (since if you have to build up a significant number of counter
That's exactly why it is played so much, and it only gets better if you're not running Scrolls. Rack is for late game, and a late game keg would probably be used more against larger threats (Morphling, Shades, etc...)
I do agree with Ezechial on the matter that you may want to up the Wasteland, especially if you don't have acces to Sinkholes.