The more I think about it, I don't think we can afford an up and comer/unknown actor to take the mantle that Bale left. Casting Batman is too important' it is why I think the best choice would be Michael Fassbender, who is a great actor with tons of range/gravitas, screen presence and would do a bang up job. He is a good looking guy, very charismatic so he could play the playboy billionaire with ease but as shown with magneto he can be a straight up convincing bad ass and Fassbender has that tough mature look and would look great under the cowl and he is only 6 years older than cavill at just 36.
Fassbender has that respectable resume with inglorious basters,hunger,shame,Prometheus,jane eyre,x men first class,etc. that would get the respect of the fan base and the general audience all very excited that some unknown just would not have