Apparently McKenzie greatly improved the film from the TIFF cut. Basically from a mess to quite good. They should delete all tiff reviews on rottentomatoes since no one will ever see that cut and it’s a different movie. Would have a fresh score if you deleted the tiff cut reviews for sure.
Allstar raises a good point in general. I've been bringing up this problem for years to the deaf ears of my fake colleagues.
For example, You Were Never Really Here (one of the best movies this year and a masterpiece) had a few significant changes between Cannes and theatrical release. So for better or worse, the cut reviewed at Cannes is not the cut reviewed here.
Apart from the fact that I'm not certain Mackenzie can direct, and the common cheapness of action scenes at night, the story is thin-to-non-existent. Bruce becomes king and then is ritually hounded and loses his family before deciding to have a battle. That's... not a story. The characters aren't challenged by anything, apart from the Prince of Wales getting some stern but mild disapproval from his father, and Elizabeth de Burgh showing stronger leadership qualities than Robert (a high-quality funny).
There's also a strange comic tone that pops up here and there but that's insignificant compared to the lack of any real storytelling. If you're going to have a film about a man becoming king in the most extraordinary circumstances you would think the film might be about that? Instead of just "some people joined him, and some didn't, and the English were dishonorable so he made his army go and fight them!" Even Braveheart concerns itself with these issues better, and gives itself a Death With narrative to anchor and propel the action. Even Bruce in that film is depicted as a more complex, challenged character.
It's an absolute nothing that is built on whiffing the fumes of GoT without understanding what makes it work. And that's kinda criminal when you're dealing with something as fertile as the Wars of Scottish Independence as your material.