Youks has value due to his affordability and age, and is a tradeable commodity, but he will not bring anything close to Arroyo back on his own. He is probably as good as he will get. His ZiPS projection for next year is pretty much a flat line. I'm not denigrating him: like Pedroia, he's a guy who is getting the most of of his package.
Staying on topic, Spann is pretty exciting - the kid's just 22 years old. Just needs to control the zone a bit more, but he has the time, right?