Yes, pipelining is on. I've been doing some further testing and I suspect some of the nested roles we're using are the source of the slowness, because for simple playbooks and simple tasks, the speed is comparable (Ansible 1.9 still comes in a little faster, unless I enable the `free` strategy in 2.0).
[ssh_connection] pipelining = True
Ansible 2 is extremely fast for me.