Ionic 2 Android builds Mega-Sluggish

While our app runs really fine on iOS, on Android it is mega sluggish. Clicks on Buttons get registered only the 4th or 5th time, Transitions using md-* are slow. I am using a Z3 by Sony a pretty fast Phone imho, still sluggishness is almost unbareable. I now tried Crosswalk and everythings runs super smooth, but customers would have to install crosswalk app, which is NOT an option. Any ideas how to speed up or debug this UBER-Sluggishness on Android?