Disney is looking to move Captain America 3 away from the May 6, 2016 date as that is when Batman vs. Superman is slated for release. Despite Captain America: The Winter Soldier making loads of money, the studio would probably feel better staying away from that movie. The head to head battle would certainly be interesting as Cap has gained a huge momentum which may only increase after the next Avengers film scheduled for 2015.
With some concern on what direction DC is going with their franchise, one could see some inherent weaknesses with Batman vs. Superman. I guess there is no reason to pit the two franchises up against one another. Both will do will and I can't imagine one defeating the other and ruining the other's franchise.