Simply Buff the low tier characters so they can compete evenly with S tier characters, then you can call the game balanced. Being good with S tier characters doesn't mean you are good at the game, pick up a mid tier or low tier character and expose yourself on how bad your footsies, execution, and general game sense is. It is personally amusing to see how bad players are when they can't use Batman's J2, or Black Adam's fullscreen combo starter Divekick and ridiculous movement, KF slide, Supermans F23 Breath, Green Lantern's Low and overhead starters (GL mains on TYM are as bad as smoke and reptile downplayers), etc. When these characters are either hopefully brought down to earth, or the lower tier characters get buffs to become viable against them your going to see alot of people here exposed.