So many points to address ...
Lee vs LaRoche. I find it hard to see how anyone could argue which is the vastly superior player. Neither are stars but are decent players. Both had are solid defenders and produced similar numbers last year, with LaRoche being slightly better. When you add in age, I don't see how anyone can flat out say that Lee is the b etter player. Maybe he does have a better 2011 ... I don't see how you can sit there and say unequivocally that he's the better player. Based on their ages, its more likely LaRoche will maintain his numbers and Lee will have a bit of a decline.
Replacing Dunn and Willigham ... You do realize that Werth plus LaRoche is a considerably better duo, offensively? Those two hit for a higher combined average, knocked in more runs, while having just 2 less home runs. That doesn't factor in Werth's ability to steal 20 bags. The fact that they are much, much better on defense means its a pretty large upgrade. I know Im making a large assumption that LaRoche will be here. I will be upset like others if we don't add him, as he is the last of the definite starter material on the market. The off season isn't over and I believe the front office will add him to the lineup.
As for the comparison between the O's and Nats ... First of all, who cares? Second, the two best players on either team are Nationals. Zimmerman and Werth are without question the top two players, and both are real difference makers. Like someone else mentioned, as long as we have average players at other spots, we come out on top because we have the real all star caliber players.
When you start to break down the positions, some really are letting their negative attitude effect their thinking. Brian Roberts is entering his mid 30's and is coming off an injury riddled season. Do you really think the back will be magically healed and not give him any more problems? He's supplied a little pop for a 2b, but he was a great base stealer and was a threat on the bases with range on defense. That's not going to be the same as he gets older, especially with back issues.
Espinosa hit more bombs and had more rbi in less than half the plate appearances last year. He may not hit for as high an average as Roberts next year, but should hit for more power and drive in more runs. Thats if Roberts is even healthy. I realize offensive output isnt judged solely by those numbers, but the 2b position is a question mark for Baltimore too. There's much more potential for downside with them based on age and injury with Roberts.
I also find it strange that you just give the edge at the SS spot because Hardy is a veteran, but that doesn't mean much. Hardy and Desmond had similar numbers last year. Similar average and ops. Desmond had a few more at bats, so the power comes out about the same, but Desmond still drove in and scored more runs. Also stole more bases last year than Hardy has in his career.
Desmond is already the better player, even if only slightly. When you factor in his age and the likely improvements, he is of course the better option.
Going position by position, Id say the O's have the edge at catcher, CF, and LF(and thats only by considering Scott their LF, which is a pretty big stretch). The Nats have the better SS, 3b, and RF. I consider 2b a wash because of factors I mentioned earlier, and 1b up in the air at the moment because the off season isn't complete. If we add LaRoche, it is at least a wash. More likely, it's slightly in our favor.
Neither team is going to push for the playoffs, but the Orioles are not, by any stretch of the imagination, a far better team than the Nationals.