If you don't count Mac, looks like it may have been the triumvirate in 2012. In 2011, the Seahawks were 7-9, the Commanders were 5-11, and the Colts were 2-14.
In 2012, The Seahawks were 11-5 with Russell Wilson, the Commanders were 10-6 with RGIII, and the Colts were 11-5 with Andrew Luck.
Edit: I looked specifically for rookie QB's who had made the playoffs, there may have been a couple winning season/not making the playoffs that I missed.