People say, "If TWS opens big this April, Marvel ought to move CA3 up a few weeks to April 2016" -- but this production has the inevitable time crunch on it. Its competition, 'Batman vs. Superman' (whatever its official title will be), will begin shooting in a few weeks. Marvel doesn't even have the script ready, and at the earliest they can film CA3 is at the end of year/early 2015.
They'll need some leeway for reshoots/pick-ups too... so an April 2016 move is kinda pushing it. It doesn't need to be rushed. Besides, I think CA3 will likely play better around the Fourth of July holiday weekend because of the patriotic nature of the character.