I owned a 2015 earlier this year and now have a 2016. My friend and I went on a 1300 mile ride up the coast and he has the 2015 so we compared the two next to each other.
-Mirrors on the 2016 have way better visability, but dont look as nice as 2015.
-Tires are Metzler on the 2016, 2015 had Rosso. Seems the Rosso flat spotted more easily during thr ride so Metzler maybe more street oriented.
-Although not confirmed from any KTM source, the 2016 rear shock seems to be stiffer. Both our bikes have stock shock and both adjusted preload exactly the same. We both sat on each bike and the 2015 was more "bouncy"
-my 2015 warranty expired, the 2016 has 11 months left LOL!