A co-worker who upgraded last week to a 2016 MacBook Pro from a 2013 is complaining about battery life, too. He used to get 10+ hours and now he's lucky to get six.
At my new job, I only got a 2015 13" rMBP without discrete GPU, and I now get 8-10 hours with the same workload. It's because I don't have to power as big of a screen and a discrete GPU.
Workload matters, but discrete GPU and larger screen also matter, a lot.