I don't mind coach seats much, but the one thing that really gets me is narrow armrests and the game of "elbow hockey" that you often have to play with your neighbor.

So, the last time I was flying I was thinking about this.. airlines could give everyone in coach more elbow room without adjusting seat width at all. All they would have to do is stagger the heights of the seats a little. In a two-seats next to the window configuration, if the window seat was about four inches higher, the seat next to it could have some "tuck under" elbow room.

Seems doable. Any reason why an airline shouldn't try it?