Why they would risk the new start that they created with Man of Steel? I'm not sure. Man of Steel was the first time in, oh, forever, that Superman wasn't also a Superdouche. The Dark Knight series was wildly successful, because we cared about Bruce and his strugges.

Put the two together, and their awsomeness could very well (and probably will) negate each other, and we are left with something that could possibly ruin the legacy of both re-booted franchises. I'd rather not have an additional installment taint my love of the franchise ( X-Men 3, Alien 3-Alient Resurection-Promethius, Star Wars Episodes 1, 2, and 3, Indiana Jones: Crystal Skull... I'm looking at you).

~Jeordam