They are good enough to possibly win the NL-East division. But the Mets seem to have all their starting pitchers healthy and also have a chance to win it. The Braves and Phillies are better. So this division is up for grabs. The Nats are slightly better now than they were at this time last year, but not by much.
They need the following: a 5th starter and a stronger bullpen. Their starting pitcher depth is not strong at all; they have Hellickson and Jackson who are nearing the end of journeyman careers, and they have A.J. Cole and other AAA arms who are not ready for The Show.
Are they ready for October? Not really. To get past the first round of the playoffs they need to acquire a stronger #3 starter; Gio has never won a game in the playoffs. The Nats need to do what the Astros did last year at the trade deadline, go get a starting pitcher who can win playoff games. In addition they need to upgrade the bullpen by 2 better arms than they now have. As the season plays out up to the trade deadline and some teams realize they are not going to be playing in October, candidates for the above needs will likely appear on the market.