I really doubt that would have helped me. Since pruning all of the archived NYT's (about a year's worth) and WSJ's (about two or three months worth) off of my SD card my battery life is back to normal. My pattern had been about every month or two I'd get a warning that my Kindle memory was full so I'd grab all of the periodicals and push them off to the SD card to clear out the Kindle memory. The most recent move (last week) must have pushed me past the knee of the curve as far as how many items the Kindle could index in a given amount of time (my theory) and I was chasing my tail in trying to have that complete while untethered from the power cord.
If I was really interested in nailing it down I can imagine a series of further exercises to test this, and divine where that knee might fall, but I didn't need that content to be mobile and purging it resolved the problem so I'm happy.