SI's Joe Lemire just issued the first SI power rankings of the year. Braves #10, Nationals #12, Marlins #14.
It's a pretty fair write-up:
A full season of Stephen Strasburg, at least half a season of Bryce Harper and a has-to-be-better-season from Jayson Werth -- not to mention the addition of starter Gio Gonzalez -- should have the Nationals playing meaningful games in September (especially if the second wild card is implemented). Washington needs better all-around play at shortstop and could stand to add a true centerfielder, but once Werth, Harper and Michael Morse are all there it should have an outfield that can mash.
...although he clearly hasn't thought too hard about what a Werth Harper Morse outfield would be like defensively.http://sportsillustrated.cnn.com/2012/writers/joe_lemire/02/01/offseason.power.rankings/index.html?