Originally, there were no star-, numerical- or lettered-ratings. (Or thumbs!) There were no short cuts. One actually had to read the review.
I know. Crazy.
Gene and Roger (who I remember as good friends, as well as colleagues) did something crucial: They brought movie criticism out of the closet, so to speak. To reiterate, few people paid much attention to movie reviews but Gene and Roger popularized the form. A movie critic was formerly seen as some grumpy old professorial type, deserving of his misery.
But here were Gene and Roger, two regular guys just sitting around and jawing – not about sports but about film. And they made it look easy.
And, in turn, they inadvertently created a lot of little Siskbert monsters – clueless people who pontificate about movies and who now think they are experts on the subject. Woody Allen anticipated this phenomenon with his astute and hilarious Marshal McLuhan sequence in "Annie Hall" (1977).