The "Bautista window" is outdated thinking IMO. With their young pitching nucleus and multiple other 5-win guys, the team's 2016+ outlook is much better now than it was at the time of the Marlins trade, when the window talk all started. Not everything needs to be in sync with the timelines of Bautista and EE. The fanbase should be excited about both the near and far future.
With that said, I think Shields makes a lot of sense at 4 years, <$20M per. A playoff berth in 2015 would provide the organization with a huge wave of relief.