I, personally, am very impressed with the Nationals' offseason. With the signings of Ivan "Pudge" Rodriguez, Matt Capps, Jason Marquis, resigning scott olsen, trading for Brian Bruney, AND a very recent signing of Eddie Guardado confirmed at 1:12 ET by mlbtraderumors.com, they have drastically improved.
Mike Rizzo (Nationals GM) has made it very clear that he wants to develop his players and become better, faster. With Jason Marquis becoming a key #1 or 2 starter in their rotation (because i still think John Lannan will be the ace) he could be a great mentor to Washington's very young staff while consistently providing his 2009 all-star numbers. And with last year's top pick in the draft, Stephen Strasburg has an extremely bright future.
I think the rotation will be: Lannan, Marquis, Olsen, Zimmermann/Stammen, Strasburg. Maybe they will wait for Strasburg to develop but i think they should give him a shot to see how he does.
As for the everyday players, they significantly improved at the starting backstop position with Pudge (no offense but anyone would be better than Wil Nieves). They have a very fast and young outfield as well with Nyjer Morgan and Willie Harris. The Nationals have Adam Dunn who is a powerhouse. And, who could forget their all-star third basemen with many many successful years to come.
As you can see, the Nationals are one of the youngest teams in all of baseball and are getting better each year. With the young core of players they are putting out on the field each day in 2010, I wouldn't be surprised if they didn't finish in last place in the NL East this year (look out Mets). They have had such a rewarding offseason and I am very excited to see them play the season to come and many in the future.