You've been mislead by the games you chose to watch for both players last season and a season before i guess. Can't compare Mkhitaryan's form with Draxler's, he wipes the floor with Draxler.
Mkhitaryan has come alive this season, after being deployed to the wings rather than the central attacking role he was presented with when Klopp was there. He's also a differend kind of winger. Most wingers are known for their goalscoring, and ability to take on players rather than play-making and tracking back. Whereas Mkhitaryan does the whole lot. His distribution is superb, whilst being partnered up with his ability to cross/pass/shoot on either foot comfortably is a huge advantage. About his back tracking, he's also quite a competent defender, and is even suited to as a backup defending mid or central mid should injuries arise. He's also got one hell of an engine, and can play the full 90 pretty much every week. His biggest weakness is still his finishing, which he improved on last season. He has scored quite a lot this season, but can he fluff some easy chances, which was evident against Madrid in the CL (you watched that game) a couple years back and even against Liverpool in EL.