I don't think Johnson will be much of an upgrade. Plus, his days in LA where there was talent, he did not have great years.
How I look at it is offensively, I think this team is incredibly thin. Outfield looks awful including Werth with Storen out and I will think it will be hard pressed for Storen to repeat last yaer. I think on the infield you have Zimmerman, LaRoche, and Espinoza.
Pitching wise they should be pretty strong, I'll adhere to that. But Washington and what makes the NL East so wide open has a very weak lineup right now. I'd still put the Braves offense ahead of them and 1 game notwithstanding, Florida's offense is better as well.
I put them on the similar road to Philadelphia's offense.
Wait til next year for your adopted NL team.