The most glaring problem with Water World was that it did not have a protagonist that the audience could identify with. Same with The Postman and to a lesser degree the same with Wyatt Earp. Costner is like a cool California robot on the screen reading the lines and mailing it in.

People who don't like Costner as an actor dislike him because he does not act.

>>The critics simply decided it was time to trash Kevin Costner, <<<

because everything he does is the same character and Kevin Costner, not acting makes a great crazy Iowa part time farmer and a pretty decent washed up catcher, but is not so good as a post-apocalyptic hero or an English legend or a Western Icon.