I have doubts that this directly helps the OP, but I want to draw attention to this
Essentially, this argues that there is no regression, but a bug fix that has some unfortunate side effects in some circumstances, and that there may be work-arounds, again, in some circumstances.
To summarise, it is a semantic
argument; that is, it argues that to call it a regression is to misuse the term, in this case. (And, as far as can be told, the Phorons are pretty much unrepentant about their use of the word regression.)
While this doesn't affect the amount of power drawn by the OP's computer by even a milliampere, I tend to agree with the blog post (fewt) argument, but I will freely admit that if you are sitting in front of a computer that suddenly has half the battery life that it had previously, it will seem very like a regression.