Johnny Apples said:But going back to Berserk Project, if there was anything that is to blame on Miura's part, then I believe it boils down to this - his personality. Miura's humble, affable personality might have been one of the crucial yet overlooked factors that allowed this abortion of a movie trilogy and 2016 anime series to even come to life in the first place. At a time when firm assertiveness and even harshness was needed, Miura's amiable nature is probably what kept him from putting his foot down and forcing the animation studios to do right by his manga. He could have gave them an ultimatum - either do his story accurately or don't do it at all.
Without speculating too much about how things went down, I think people need to remember that there were no Berserk adaptations for 15 years between 1997 and 2012. When the "film project" started, it was revealed that Miura had received quite a few offers over the years but had turned them all down because they were too shitty. So aside from having been given false promises, there's also the matter of time to take into account. After 15 years, he might have resigned himself to the fact he'd never get an offer with a bigger budget, and that this was his last chance to see more of Berserk get animated.