We already have a class that benefits directly from aether: arcanist. If you are familiar with the summoner relic storyline, the crystal at the top of the (original) relic book is meant to help you channel aether more efficiently. It doesn't actually do this, but it's the lore purpose for that crystal. Also, if you look at the scholar zodiac weapon, they also have a crystal. We raise our book in the air when we use aetherflow, as well. Although the power we use itself is not in crystal form, there is already a class that functions based on aether alone. Similarly, all of our offensive abilities are unaspected -- pure aether.

I forget what the lore is for SCH fairies, but SMN pets are created by drawing upon aether as well. The size of the egis is explained through the power of the wielder -- we can only safely gather so much for ourselves. Primals, fueled by crystals and reverent beast tribes, develop a mind of their own... and disobey their 'summoners'. Our egis won't do that, because they are a manageable size. It's all very interesting lore, which I thought you may have wanted to know.