Have to disagree with most of your post. Art is subjective at the end of the day, so people are fully within their rights to dislike something they see based on a promo or based on seeing the entire series. We make quick decisions like this all the time in deciding what entertainment we want to consume or pass by.
The issue is you're assuming all criticism is based on nothing but a few screenshots but that isn't the case. At this point we have interviews from the film makers and from cast and crew. Some of the intention and direction is known at this point.
If someone raises concern over the altered timeline, that is entirely a valid criticism. And I say that because no piece of cinema has every been deemed good or bad based on trivial things like someone's costume or because of the physical appearance of an actor. Adaptations are deemed good or bad based where they decide to follow source material and where they decide to take creative liberties however.