With a total of 56 playable characters, Marvel vs. Capcom 2 proved to have one of the largest rosters in fighting game history. Despite this, only a handful of characters were considered tournament viable, and Hayato — a character from 3D fighter Star Gladiator — was one of those that missed the competitive mark.
In this article, Twin Galaxies explains how the character had a very unique moveset, but that in itself helped to prevent the character from rising in the tier lists. The character could easily make one mistake and be opened up very quickly, due to whiffs being costly for him even from full range. Check out the full article here.
Source: Twin Galaxies