That might be your opinion but they seriously have bigger fan based than rest of the cast.Popularity polls disagree.I astounded that,People actually think flat arc characters are less complex when they are more.vegeta ain't more complex than goku. You might think that on first look .but sorry ,nope!
batman is the most op character in dc now btw.So you are wrong.Story demand what kinda powerlevel a hero should have.He can leap 1/8th a mile or fly to mars.