Goku Black doesn't have anything going for him really. He's subpar in almost every aspect of being a character. His neutral game is very simple so it's easy to predict what he wants to do, he has absolutely no mix in any way so his advantage state is weak as well, and he has garbage Okizeme off of his Level 3 so he can't maintain advantage. He relies massively on his assists, more than any character ever should.

Videl is really only held back by her lack of a proper Reflect and her less than stellar normals. Otherwise she isn't that awful. Her mix-up game is amazing and she can get a full combo off of basically any attack. Also, Great Saiyaman's Ki Blast is stupidly powerful.

Captain Ginyu is a solid character. His only negative is how much skill he takes to use, but if you are good with him, he will absolutely wreck shop. He has some of the best damage output in the entire game, ridiculous pressure, and dominates neutral. He doesn't have the best mix-ups, but he makes up for them with the Ginyu Force and Assists.