The original Mulan legend is good material as is the original movie. If the new movie had been any good we'd likely all be happy for it.
A Star Was Born has been re-made 4 times. The most recent is the highest rated. Pride and Prejudice has been made several times. I personally really enjoyed the mid 90s version. Mutiny on Bounty has been re-made more than once. I liked the 60s version over the 40s version. I liked the 2005 King Kong (and the 1933 King Kong)
There's nothing wrong with remaking. It's just disappointing when it's a bad remake.