The screen can distort in a specific spot if you press the back in a specific spot. This might bother you if you A.) hold the iPad in a very specific way, or B.) if you go looking for it.
The speakers are loud and do reverberate.
Fingerprints show up a little more noticeably.
The battery needs slightly more frequent charging than the previous model.
You might get a screen with some color shifting and/or a shadow down the left edge. You might also get a beautifully even screen.
These things might bother you. Only you can decide if they do, and only after buying one to see.
But what will definitely NOT bother you is that this is absolutely the best iPad Apple has met yet. It is hands down one of, if not the, fastest and smoothest tablets ever made. The screen is crisp and punchy. The UI is quick and responsive, as is the wifi (except for a couple of iOS 8 glitches). The hardware is light, and thin, and a pure pleasure to use.
The iPad Air 2 is what tablet computing is meant to be. No iPad before it has been this close to idealized.