My post yesterday had a distinct "Losers Forever" feeling to it and I didn't want you to get the wrong impression. Just because the Nats can't be winners now or in the near future doesn't mean the team is being managed poorly. (It does mean the team WAS managed poorly but that's a different post)
In my mind if the team keeps going the way it is - signing draft picks, stockpiling what minor league talent they have, making smart free agent signings and the occasional smart trade - they can keep moving in the right direction. Talent wise they'll get let's say 5 wins better every 3-4 years, and will top out probably in the 80-85 win range before there has to be some change in strategy.* When talent wise you top out at 85 wins well then in "good years" where everything is clicking you can challenge for Wild Cards or pennants. Of course there will be bad years in this decade long march. It won't be 1-2 wins more every years. More like 2010 : 71 2011 : 76 2012 : 73 2013 : 77 2014: 78 2015 : 82 2016 : 75 2017 : 84.
* At this point I think you either have to start raising payroll to be in the top of the league or you ned to "go for it" during a "good year". That'll give you a couple year run at the pennant if you're lucky but knock you back down a couple ladder rungs later.
Of course real good luck or real bad luck can mess with this plan. If Bryce is the next Pujols that helps speed things along. If Bryce is the next Shawn Abner that slows it down. That's just the way it works. Every team not throwing money around is going to need some breaks along the way.
Trading Dunn, Livan, Guzman, would be part of this strategy, though it would probably mean next year would be a slight step back, say 70 wins instead of 75. Not trading them would delay the progress for the sake a few more wins in the next couple years, but with a little luck and a savvy signing or two that could mean a WC challenging team. The only thing that would be detrimental to this team would be losing what little minor league depth they have. Dealing several guys under 25 in a quixotic run to 88 wins would be a mistake.
The team is on a boat to respectability, it's just a slow one.