Yoshimattsu : My nightmare character would have to be Steve, he has the ability to pretty much dodge anything you throw at him and recover swingin'....Also he is one of the only characters that a button-mashing noob and a master player can do very well with...I like using Steve on occasion, but when I have to fight against him, there aren't many strategies that consistently work efficiently. Throwing him frequently works with some people, but if they are well trained at throw escapes, there isn't much you can do to him except throw many distance attacks at him and hope for the best.
Agreed, Steve is annoying.... but Any of Yoshi's power hits (T+1+2 or 3+4) interrupt him nicely.
For me, its not "Nightmare Characters" but more along the lines of "Annoying." My listing includes:
Zafina, Leo and Miguel. Watch any good player on YouTube vids and they have some sneaky low/mid hits that appear as others on startup. I hear the scrubs lining up already....
Julia/Michelle. I dunno why, but they just aggrivate me by default. Im assuming its that subconscious, misleading Low/Mid Priority startup.
Steve. See above. thanks for putting it that well Matt!!
Ganryu. I just hate him. No reason really.
Paul. Scrub Friendly and a true slugger. 2 clean hits and youre a gonner!!
Any Sub Par Yoshimitsu player who is not Noko.:D Stop putting Yoshi in a disrespectful position!!