9. Oliver Queen's Personality
Oliver Queen wasn't the first larger-than-life billionaire playboy to moonlight as a masked vigilante, so it was up to DC Comics to ensure that their Emerald Archer had an entirely different personality than their Dark Knight - something they accomplished by making him a more light-hearted, fun and quip-filled alternative. But that's not the version of the character we saw in the Arrowverse.
On Arrow, Oliver Queen was introduced as an emotionally-tormented individual, seemingly dead on the inside while showing very little emotion on the outside. Understandable side-effects from his time on Lian Yu, but ones that never really left him throughout the course of the show. And this sombre variation of the Green Arrow understandably drew comparisons to Batman.
It's hard to deny that the darker version benefited the show. He was everything Arrow needed him to be, so in spite of the DC Comics' fans protests, there's no disputing how he was the perfect fit for the show. Where the writers failed Oliver, however, was when they let the similarities between the pair blind them, as they began to feed him Batman villains, Batman storylines and even a Batman character arc - something that earned their Oliver the not-so-affectionate title of 'Walmart Batman'.