look, Takamaru is cool and all, but Lyn has
1. the first fire emblem game released in the west
2. the massive boost of popularity the series got from Awakening (not to mention it saved it from being axed as a whole)
2. already being an assist trophy in the game
I just think that one more FE rep, the most popular of the three lords of her game despite her (and Hector) being secondary to Eliwood, from the most universally known game in the series at the time of Brawl's release is more than justified.
actually, does anyone else have the same beef I have with assist trophies? to me they're not much more than "look who isn't playable!" items that fall into Brawl's redundant armoury that made myself and all my friends turn off items way, WAY before P:M was released.
and hell, why not both? there's 5 slots left. If 2/3 of those characters end up with swords (Lyn, Takamaru, Isaac), they're all characters that can easily have movesets built to focus less on actual swordplay. okay, less so with Lyn, but she's at least got a bow to mix it up.