I'm sort of obsessed with matching up DC characters with their Marvel equivalents. The big two have copied each other since the beginning. I really wanted there to be another crossover. I remember the really ugly Almagam crossover in the 90's that was unsatisfying. I recently learned that they did a JLA/ Avengers crossover in the 2000's. I am trying to get a copy of it to read.
I started imagining a story where Wonder Woman would fall head over heals for Thor. Also would love to see Batman and Spiderman face each other's respective rogues gallery. I think a crossover would be great as a charity event. Both companies have similar multiverse concepts going currently with multiple versions of earth. It wouldn't be hard to have DC's Earth 1 and Marvel's Earth 616 cross paths.