What I'm saying is that it's enough to get people to care. The movie certainly has to stand on it's own, but if both movies are equally good, I'd give the edge to Superman/Batman.
I certainly agree that Marvel has the better strategy and recent history, but if DC makes a Justice League movie that's on par with how Man of Steel looks and The Dark Knight trilogy, I think DC could win the summer.
I don't think this is the case, but there is also the possibility of the GA being worn out on the Avengers team in 2015. If they lose steam that could hurt both franchises.
I also don't expect Avengers 2 to bring in the same amount as Avengers 1. Kind of bold, right? I feel like the first invited more of the GA because it was an event. The deeper that these go, I believe the nostalgia will begin to wear off.
This is all obviously just my opinion, so who knows.