It's hard to think about how eden couldn't be.

She has by far the best attack of all the GFs, the most interesting sequence, she can help you raise your stats (with devour), she makes you lucky, can save on your magic, she is the most secret to find, she lets you refine some of the neatest stuff in the game (gf abl med has items that are totally unique, Hundred Needles, Glow Curtain, etc)

But she's not nearly as cute as Carbuncle! or fascinating as Alexander!