Yeah, but you can "bite the bullet" without giving up one of the top prospects in baseball for two years of a fringe ace.
Just look at how much money they would've had to spend if they'd built their rotation differently. They took on $12 million in the Santana deal. They spent $25 million over 3 years on Guthrie. They will be paying $21 million over the next two years for Shields and $7.6 million for Davis (both good investments...but still money). And they will be paying Hochevar about $4.5 million in arbitration when they could have just non-tendered him.
That's a total of about $70 million committed over the next 3 years. They have only one impact guy to show for it, and they're better off without 1-2 of those guys (Hochevar; maybe Santana). For that money, it seems like they could've gone to the free agent market, gotten two good starters in the Jackson/Lohse/Dempster class, and then filled in around them with reclamation projects/guys who fall through the cracks/minor trades. Sure, they wouldn't have the ace at the top. But they could've probably found a much stronger back four.