For me it is a tie between Mega Man and Shulk. Both of them got fantastic movesets, and I like to play as them both. I also like little mac because of the one hit ko punch (it was a good mechanic). Pac-Man is also very good, and my little Brother mains him and villager, another great newcomer. Duck hunt duo and dark pit is really good to, but dark pit is kind of a pit clone. Luucina is also a clone, but I like her to. But Robin and Bowser jr are great original characters, and they rock! And we must not forget the awesomeness of Greninja and rosalina!!
I just realized that i mentioned all newcomers...