Sorry for the confusion. Maybe I should have left the speed portion out of that discussion. I was just using that to point out that different people do better with different builds. People with fast reflexes, for example, make pretty good mesmers.

I agree that Ether Prodigy has nothing to do with speed. My theory is that it's a counter against mesmers. They can deny energy and strip enchantments all day long, but Ether Prodigy will always ensure that your ele stays in the game. My guess is that Ether Prodigy is a must-have in tournament play. Just look at WM's mesmer's skill bar in game 1 of the finals. Energy Denial: Energy Surge, Energy Burn, Power Return + Enchantment Stripping: Drain Enchantment, Shatter Enchantment. Ether Prodigy is a great counter to that. You're always deliberately low on energy, so that makes Energy Surge and Energy Burn pretty worthless. You're obviously not going to rely on enchantments (given that Ether Prodigy will strip them anyways), so that makes the Drain Enchantment and Shatter Enchantment useless too. With that one skill, you've made 5/8 of the mesmer's bar irrelevant.

For PvE and/or Team Arenas, I'm not so sure. I've never had problems with energy management in those environments, so I can think of many other elites that I would rather use that don't require me to lose all enchantments or take exhaustion. That was really my point. Illidan seemed down because he "got bored" of the skill, but it may just not have been useful in his particular situation. Another prevalent example of this is the 55 build. It's great for farming, but pretty worthless anywhere else.