When you pull down spotlight and rotate iPad Air 2, it's not perfectly smooth 60 FPS. It looks like 30 or less. It doesn't stutter like 6 Plus does when you first rotate it. I suspect because it doesn't have to load a different keyboard.
Yes, it lags, just like all my other iDevices. I decided to try and reverse engineer iOS, recompile it and run it on my I5-2500K running at 4.8GHz. When I turned the 30lbs PC tower on its side, the keyboard lagged of my desk and onto the floor with a loud bang. Conclusion, it's an iOS problem. Gotta go buy a new keyboard now. Darn it 😉