Loved Bale's voice. There is no accurate way to voice batman, it's all subjective. There just has to be a low tone since I remember that being the description in the source material. Even Conroy went lower. But I don't want to hear it again. To me it was a Nolan/Bale thing...so even if Bale returned with Snyder at the helm, I think it would at least be like his Begins voice.
A return to the Keaton approach is perhaps the most universally accepted so I would go with that for the reboot. Conroy's is still THE voice but that wouldn't work in live-action I don't think. It's too obvious that it's Bruce Wayne. When you're a fanboy you can suspend disbelief because of your love and commitment to Batman, and when you're a kid (which was the target audience for BTAS) you don't think of those things. Chances are if you're an adult watching the animated series it's because of nostalgia, you were a kid when you first saw them or you're basically a hardcore fan. So the Conroy voice cant really work in live-action, general audiences would call ******** on that.
Michael Keaton's voice is the way to go. To separate itself from Bale and to win back the haters. But yeah, I still love Bale's voice. His version had a strong emphasis on "channeling his rage through batman, becoming a beast, a creature". So it worked.
Id like the new Batman to be calmer, more collected, quieter than Superman.