I think the idea of looking to deal a SS if you also have Castro is right -- there's definitely a good deal out there for a player of Hanley's caliber. But I don't think this is that deal. Lee is an excellent pitcher, but just isn't even value for a guy who can be a first-round talent when he's hitting. Add in the dynasty component and Hanley's relative youth compared to Lee swings the pendulum further.
To give you an idea of Hanley's value, I gave up Ryan Braun in a trade earlier this year to get Hanley (not straight up, there were other players involved, but still)...
I'd decline and see what else is out there.