I find that highly annoying then! Its like someone takeing your own characters and totally changeing everything about them...
To be fair, Don Bluth didn't even create the characters. He did a lot of great work with them, no doubt, but he didn't create them. That honour goes to the two people who are credited with creating the characters in all the LBT films. In the original, they have the story credit, and in the sequels, there's always a bit in the credits that says "Based on characters created by such and such."
Yes, in case you haven't realised, I've forgotten the names of these people, but I do know that they weren't Don Bluth.