Numerical simulations of the textbook neutrino-reheating mechanism for core collapse supernovae frequently fail to match the most fundamental observable property, an explosion with roughly 10^51 ergs of kinetic energy. This failure raises the suspicion that the neutrino-reheating paradigm might not be the whole story of the core collapse supernova mechanism. One weakness in the current generation of models is incomplete nuclear and neutrino physics. In particular, electron capture on nuclei, the most important weak nuclear interaction to the dynamics of stellar core collapse, has been treated in a highly parameterized fashion, if not ignored. With realistic treatment of electron capture on heavy nuclei comes significant changes in the hydrodynamics of core collapse and bounce. We discuss these as well as the ramifications for the post-bounce evolution in core collapse supernovae.