I'll keep this short.
The problem with another mishandling of Tarzan is the repeated attempt to turn the material into epic drama or take itself too seriously. Burroughs' creation is truly great pulp. In that sense, it is classic American literature -- but not in the 'great literary' sense. And that is Tarzan's appeal.
This new film is uneven. The scenery and locations are perfect and satisfying. I want to see those places. The costuming and props are also perfect, the visual experience of the film fitting of the genre. However, the writing is not satisfying. It's simply not well written and I question the writers' grasp of the true appeal of the original material. The story flows good then 'blah'. The villain isn't up to Christoph Waltz' talents. Alexander Skarsgard as Tarzan is reduced to the two-dimensional image that epic-dramatizing is supposed to give further dimension. The casting is actually pretty good but wasted. I enjoyed Ben Chaplin's small bit early in the film. However, in a movie about Tarzan, I'm not supposed to come away more interested in a film about Samuel L. Jackson's character. And I did come away from Legend of Tarzan more interested in seeing a film about Jackson's character.
I think it's about time we saw a Tarzan film not just based on the Burroughs material but actually adapted from what Edgar Rice Burroughs successfully envisioned. Legend of Tarzan ain't it.
Still, for us die-hard classic adventure fans, I give it an 'OK' and recommend you see it at least once.