This is actually pretty false. WyomingMist posted a video he made of all the PTR changes compared to Live, and in the video, Reaper when shooting Hog from the front killed in the same # of shots on both versions up until a certain range.
After a certain range, (as you can see in OP’s linked graph) there comes a point where ExC Reaper kills in one shot faster/sooner than Live Reaper would (again viewable in WyomingMist’s video).
So no…Reaper did not get better at non-tank combat while slightly worse at tank combat. In fact, as his video demonstrates, Reaper is NO LESS effective at killing Tanks when shooting them from the front with some headshots at any range AND in fact becomes more effective after a certain range away from the target. AND he is now better at fighting non-tank targets at ALL ranges to boot.
Reaper portion starts 0:26 into the video