For those who I agree with on 'MOAR FE REPRESENTATIVES LOLZ'... here's my speculation on original non-sword using FE characters becoming playable characters in Brawl:
Micaiah from the recently released Radiant Dawn, sequel to the game Ike is in.
She's a mage, a mage hero class which was a first in the series(I believe)in case no one else has noticed. A mage like her in Brawl can only be pictured as another Zelda as to rarely throw punches or kicks and just let the magic do the work, except she relies more on the magic. Seriously, she's so fragile a gust of wind would break her in half. She's original enough, magic-using characters deserves some loving.
Ephraim from FE8: Sacred Stones, the 'first?' hero whose primary weapon is the lance. He's not too original since he slightly resembles both Marth and Sigurd, take a guess how. BLUE HAIR LOLZ. Seeing a lance user in Brawl would be a first, making it very unique. The character appearance may overthrow some Marth fans. But A LANCE-USER IN BRAWL?! *head asplode* He's probably right up there with Micaiah in originality if appearance is no concern at all.
Elinci--nope, forget she uses swords.
Hector from FE7, prequel to Roy's game and pretty popular lord since he had great stats for a heavy-armored Axe-user. Yup, he's an axe user and looked badass with one. The great debate on seeing him in Brawl was the fact that Ike already claimed the 'slow but powerful, no INSANELY POWERFUL' spot. Now, Sakurai eliminating any clone movesets and/or characters with it, he'd have to break apart what he never wanted, making Brawl have characters with indeed cloned movesets again. It'd be difficult to give Hector a completely different moveset from Ike after some thought.
Edit: I just remembered that Hector has blue hair too.
Dubba-you-tee-eff?!