From a Nats perspective, we ought to be happy that there are high prices being set for premier guys being traded in July.
ESPN uses some sort of playoff projector (not BP or coolstandings) that says the Rangers went from 95% likelihood of making the playoffs and 15% of winning the pennant to 99+% playoff chance and 30% chance of winning the pennant. Lee was worth 3 extra wins by their calculation, which is huge if you are a marginal contender. They were better than marginal, but still it is a big impact.
The other thing I see batted around all the time is a study on the value of Type A compensation. It is about $9m in terms of WAR. I would still expect the Rangers to offer arbitration to Lee, more or less expecting him to turn it down to get his big long term contract rather than take a one year pay out. So in essence, they get Lee, Lowe, and $9M in talent back in this deal.
Lowe was always talked about as a potential closer. He's coming off of injuries, gives up too many flies, and has been a bit too lucky for my tastes, but I don't think Daniels goes for him if he did not think he could at least be a 7th inning guy to pair with Darren Oliver. If he can close, or if he can take over the set up role and allow Frank Fransisco to go back to closer, then they might be able to move Feliz back into the rotation. If that happens, then this is a great deal for this year.