system
A chat on subreddit /r/pcmasterrace
human
The one most people will seethe about is Tom Bombadil, but he's so weird that I'm actually glad they left him out.

The one that peeves me the most (my wife more than I, but it still bugs me) is that they make Eowyn and Aragorn have this weird love chemistry that just isn't there in the books that turns eowyn into a melty girlish puddle. Eowyn loves aragorn, but it is completely unrequited and is treated as little more than a crush and they don't even speak until RoTK and it just felt unnecessary. Not that behaving 'girly' is in any way bad, it just feels very out of character for her and shoehorned in by hollywood. According to Jackson, he was actually pressured by Hollywood script doctors to remove Arwen entirely so him and Eowyn could have a romance, it plays out like this was the compromise (that's just my guess, I don't know for sure).

The army of the dead was also never at pellenor fields - that was a victory through mortal strength and shrewd planning and assistance from Aragorn at the head of the Grey Company which was entirely left out and would have made the 'Return of the KIng' look way cooler, and the army of the dead kind of kills that because they show up and just murder everything. That being said, the charge of the rohirrim is one of the greatest scenes ever put to film and the emotional weight is there because the battle was hopeless and they knew they were charging to their deaths, so the decision has some artistic value for sure.

My brother is personally pissed that Saruman's invasion of the shire (and the fact that he survived) is removed entirely, but I can understand why that decision was made because it makes the screenplay flow much better, even though the hobbits fighting would have been awesome.

I haven't read the books for some time, those are the ones that stick out in my brain. In a vacuum, none of these are bad filmmaking decisions, per se, they all work in the context of the movies, but as an adaptation there are things I would have loved to see in there that weren't or vice versa.
gpt
And legolas using a shield as a skateboard, it's what Tolkien wanted