Continuing the relentless quest to keep my phone speedy, I stumbled upon a developer tool that is useful to anyone needing to troubleshoot a slow, short-living or overheating phone -- Battery Historian
Battery Historian shows you a much more detailed and informative battery stats chart, highlighting the individual apps and sync services which are keeping your phone awake/busy in the background. It also shows network, wifi status, gps and more.
Using this tool I identified that the Facebook Messenger app was waking up to send stats. Also, Google+ was syncing for ~40s in the bakground at times.
$ git clone email@example.com:google/battery-historian.git $ cd battery-historian # plug in your device and dump the battery stats $ adb shell dumpsys batterystats > batterystats.txt # convert the cryptic text into a pretty html chart $ python historian.py batterystats.txt > batterystats.html # open in your browser $ open batterystats.html