Because unlike other Robin Hoods, he can speak with an english accent.

facts.

Michael Wincott and Alan Rickman chewing the living fuck out of the script is a sight to behold.

What makes you different from all the other Robin Hoods?

Unlike them, I can speak in a British accent!

facts

it's fun and when Costner actually stops trying and starts doing the Erroll Flynn it is even clicks for a bit. Rickman and Wincott are fucking delight. So much scenery chewing.

Same, every time I see it I’m transported back to the summer in high school when I saw it in the theater at the mall with friends. So much damn fun that even Costner’s dumbass accent couldn’t ruin it.

The sheriff in any Robin Hood is a Bad Guy©

he has a point though.

the baddest

Costner would've been less out of place if that movie was a Connecticut Yankee adaptation.

I think it was around the time he was filming M. Buttefly with Cronenberg. Back in the day Irons tried to avoid his fellow British actors tendency of working on genre films - folks like Sands and Payne eventually settled into villain typecasting. Rickman didn't gave a shit and just knocked it out of the park all the time.