Zelda has a bunch of spells Link used before, when she only transformed into Sheik. Frankly, Sheik has more canon skills than Zelda.
Ness had potential movesets, but uses other people's moves from his series. Captain Falcon never actually fought before the manga/anime.
Peach is actually almost a worse offender, but her lack of moveset potential (far worse than any lack of potential Palutena has) was still put together into a really interesting moveset.
Palutena herself actually gets a full moveset for even a small moment of Uprising. Not to mention she has limitless goddess powers. And whatever a Glam Blaster is. It's fine if you "can't see it" or don't want it, but to ignore that other characters haven't "seemingly" had potential before, only to be made into something very interesting, and say that the same probably won't happen for Palutena, is just silly.
As a side note, all Fox and Falco did before 64/Melee was fly around. And when they were on the ground, they had a SINGLE laser. Which seems to be the complaint about Palutena. She at least has a staff and a shield. So...