In another thread it was posted that nothing is known about time delay coming on 12V MAX.
As for the batteries and the buttom working in a straight downard vs. back function, I think it's a packaging issue. Look at these posts of the batteries disassembled:
12V MAX
http://dewaltownersgroup.com/index.php/topic,387.0.html20V MAX 1.5A
http://dewaltownersgroup.com/index.php/topic,816.0.html20V MAX 3.0A
http://dewaltownersgroup.com/index.php/topic,817.0.htmlNotice the battery orientation is different in the 12V MAX (parallel to sides) vs the 20V MAX (perpendicular to sides). It looks like perhaps the parallel packaging in the 12V MAX and the battery contacts doesn't leave the extra room needed.
I could see them extending the length or height of the 12V pack by the 1/4" or so needed so the battery release tab could push straight downward. Didn't the 12V MAX hit market before 20V max, so perhaps the made this battery release change after 12V MAX was finalized and 20V MAX was still in development? I could see this change being made to the 12V MAX batteries without needing to be concerned with changing the model # of the battery, since it's so insignificant.