I strongly disagree with you in this (maybe because i am huge geek).
The fact that it is made up world doesn't justify changing things. That "made up" world is made by someone and it has his fans who love it exactly just like it is.
Lotr, Got, Star wars, Star trek, fairytales...are all unique and should stay how their creator created them. Butchering those stories are just insult to their fans.
You either film it how they are or don't. Also nobody is stopping you (producers, not you personally
) to create new world and sell it to audience? No problem. Hire writters to create new original story and film it. But it is easier this way...lets use something great which has big fanbase and ride on that train.
But that is just my opinion. We are all different i guess