I am of moderate height and have never had a problem with leg room although I am quite flexible. I know some others do, and in a big way. Assuming you can overcome the leg room issue, here is a little trick I learned years ago, back when you had to enter the balcony through a separate door. The sight lines are fine in the center balcony, the problem is that the front of the balcony can occlude a decent slice of the downstage area depending on how the show is staged. But if you buy seats in the back row, especially in front of the booth that is up there, you can sit on the end of the seat (the part that's up when no one is sitting in it) and this gives you all the sight line you could ever want (except maybe if the show spills into the audience as it did in Hedwig). As a side benefit it gives you all the leg room you could ever want. 