Was Johan Santana's trade worth it?

In 2008 when the Mets were able to land two-time cy young winner Johan Santana the deal looked like a steal. Although they didn't give up anything thing, as the star prospects they gave up to Minnesota, some of them never made it past triple A. A good example of this would be pitcher Phil Humber known to be the best player in the trade never lived up to his expectations. But the Mets still gave Santana, at the time the biggest contract for a pitcher ever. Recently Santana has also declined as his speed on his fastball has went from a 94 mph fastball to an average of 89 mph on his fastball. He also missed the last half of last season and is set to miss at least the first half of this up comming season due to an operation on his throwing shoulder and the question has to be asked will he ever be what he was in Minnesota? or just a mere glimpse of his past. If he doesn't return his greatness the Mets would have to still pay him a 20+ million dollar contract for the next three years plus a club option and if they donn't pick up that option there is a 5.5 million dollar buy out. So while there are some recent negatives to the Santana deal so far he has pitched as the ace that he was brought here for but only time will tell if the trade was worth the Mets had to pay.