Worst? Palutena seems decent, but her default moveset is rather bad and hard to work with. Zelda is by far the worst, having no real options, where everybody else has fairly decent weapons to fight with regardless. Jigglypuff is still quite amazing, as only Brawl was her bad moment in Smash history.
Outside of patches, Zelda just isn't really savable. I do admit MegaMan may still be on the low scale, but we'll have to wait and see in the actual meta. Ganondorf is still a bit low, but his approaching options are still difficult outside of custom equipment/moves.
I'll eventually get more competitive knowledge when I have a usable Control Pad to participate at a more reasonable level and I fight more human opponents offline. I do admit I overuse the customs, but I feel they make the game a lot more fun.