Interesting. I called today about my 6s as well. Never said 10.0.2 would do anything to the battery. In fact I found their questioning and suggestions pretty pedestrian. They ran the diagnostic but the conversation ended with basically an open-ended "OK then, good luck"-ish sort of non answer to the issue.
Exactly. I got the usual scripted line of "Try dimming your screen brightness and closing some apps". I said, "On iOS10, I will open messages, type 4-5 words, and can watch the battery incrementally decrease 8-12% right in front of me". They ran the diagnostics, said everything is fine, and asked me to check if there's an update available, which I did, and they used it as a quick "get this guy off the phone" tactic, "ok install the update and see how it goes, if there is still an issue you will need to do a full restore". Sure, thanks, bye.