Brad Wilkerson is Adam Dunn lite, but with good speed, better defense, and the ability to play center field. Just like Adam Dunn, people aren't sure where to put Wilkerson in a lineup. They don't hit for average, strike out a lot, but also have good power and draw a lot of walks for a high OBP. I would take Wilkerson over Brian Anderson in center field in a second.
And the Nationals would definately laugh at us if we offered only Marte for Wilkerson.
The Cubs didn't re-sign Burnitz because he was absolutely awful in the second half and finished with a .757 OPS. That's terrible for a starting right fielder.
Murton will start in left field. He's not good enough defensively and his arm is too weak to play right field. They will still need to sign or trade for a right fielder.