Let's be real here.
Ferrer's been around the Top 10 for, what, seven straight years now? Top five for five straight years, I believe. Even was #4 in 2008.
Let's go over all the arguments they had on the guy.
"He's only made the semifinals of one slam, and just the quarters of others" - Now he's made six semifinals, and only Wimbledon's left in that area.
"He can't win a slam...he hasn't even won a shield" - Paris took care of that. Now it's "Now he's only won ONE shield".
"He'll never ever get to a grand slam final" - If Bercy was any indication, any tournament can have the weird and wacky things going on, like everyone falling out, and Daveed getting his chance.
What's going on with Ferrer is between his ears, and that's it. Not only beats, but SPANKS 6-10 in the world regularly. Murray, regardless of surface, doesn't really scare him. They've had some real good matches against each other over the years. A healthy Nadal? Ferrer doesn't believe it at all. A hurt Nadal? He's out for blood.
Djoker? On clay it's obvious by the record he believes he can win there. Any other surface...not a chance.
Federer could have all his limbs chopped off, and on life support with a priest reading his last rites, and Ferru won't believe he has a chance.
Right now, pure and simple, it has to do with belief. If Plies finds a way to get through that fear wall of his with any of the big monsters, and he finds a way to win, Daveed might get incredibly dangerous.
If not....20-30 titles in a career, a shield(or more), and number 4 in the world is a career so few have ever had, and he accomplished it. Nothing to sneeze at.