The 70's was probably the "best" purely because it had so much variety. It had everything from disco to punk and everything in between. There was something for everyone. The 80's is by far my favourite decade for music, but 70's was certainly better when looking at it objectively.
I like that it is ambiguous but I would like to get to a more definitive answer. I saw almost all the clips, but I know they can't fill in all the blanks.
I would absolutely love to get a more definitive answer. I'm pretty solidly in the twins camp, but I can agree that there are arguments for multiple personalities. I don't think either theory is flawless, so it would be very interesting to get official word at some point on what the truth is (if there even is one.)
I like the ambiguity and I kinda hope that Sam Barlow doesn't clarify what he believes to be the true explanation. It has been clearly constructed to make both theories seem both plausible and implausible at the same time, so maybe there isn't even a "true" explanation and the idea is that the player just makes up their own mind and that is the story to them. It's super interesting seeing the debate, in any case.
I'm pretty sure what happened here is that on Thursday evening someone at Iron Galaxy needed Dave Lang's go-ahead to implement some stuff in Arkham Knight that would have totally fixed all of the issues. But for some reason, Mr. Lang wasn't answering his phone and the game remained broken.