Adel was a wasted opportunity of a character (Eh, may have spoilers)
Adel is talked about, feared and mentioned a great deal throughout the game, but she only has about two spoken lines in flashbacks and then, when you finally meet her, you put a ferocious beatdown on her (or she on you, depending on how good you are at junction/tactics) and never see her again, though it is implied throughout that Adel is pure evil, avarice and selfishness. I think it's such a shame that we never really learned any more about her explicitly, other than the fact that she was basically not very nice.
Story wise she had the potential to become a much greater threat than she proved to be, although I guess you could say that another purpose she served in the story was to show just how powerful Seed truly was: they were indeed capable of taking down any sorceress, no matter how powerful or dangerous.
An interesting point I found on the FFWiki, though, is the text at Timber TV Station: the "noise" broadcast over all the frequencies is in fact lettering that spells "I WILL NEVER LET YOU FORGET ABOUT ME", "I AM ALIVE" and "BRING ME BACK THERE", theorised to be the thoughts of Adel confined in space... probably the only other direct communication she's ever shown to have with the player.
What does everyone else think? Would you have liked to see more of Adel in the story?
And what the hell is she, anyway? She's like fifteen feet tall and Laguna calls her "human" still...