I believe the terminals are placed on the bottom so that the crossover components can be better isolated. If you can access a cut away view of the speaker you'll see why. As a practical matter, I can see why you think it's a pain.
Any one else have this complaint?
I have avalon speakers and the binding posts are on the bottom, and it is a huge pain to change them(speaker cables). I believe Vandy's are the same way. I just changed speaker cables again and it take about an hour to tip them over change the cables get them back on the spikes and then close to the right spot , and toy with them getting them perfect over the next few days. With some speakers you don't have to do this, it is enough of a pain that I would not get another pair of avalons for this reason- am I the only one who thinks it is as annoying as it is? their must be a better way!!