Lets talk about Nash in terms of what he brings to the table and what he doesn't .
Overrate: Nash is a stud power forward with soft hands and a hard accurate shot. Nash makes any team he goes to a contender ( mostly due to the list of teams he wants to be traded to ) . Nash on a line with a play maker could net you 40-45 goals. The only real impact scoring winger still available ( that's not Russian ).
Now on the flp side
Underrated : Nash hasn't proven Much (aside from a 79 point season and a couple 40 + goal campaigns) in 9 seasons. Nash lacks the ability to get his team in the post season. Nash's attitude that has been questioned in the past. Nash lacks the foot speed needed to separate himself from defenders. Nash and his fat contract.
So when dealing with Nash it really depends on which side of the fence you stand on .
The truth is that Nash could really go either way once he's traded. He might help raise a cup or burry a team with his big money contract. Time will tell , but for money I would steer clear of this one.