Cleaning up the picture? Nope, doesn't bother me.
When the film is actually altered? I'm usually against that.
However, if there's going to be a new cut, such as a director's cut, and that involves adding scenes or clips that were recorded but unused, I'm generally okay with that.
Example from Star Wars: the scene added in the Special Addition of A New Hope when Han talks with Jabba. I think it adds a little something to the Han/Jabba dynamic when we see their discource here as opposed to not seeing Jabba until Return of the Jedi. And adding this scene doesn't really detract from the rest of the movie in a significant way.
On the other hand, if an original scene is strongly altered from the original, for no compelling reason other than "the producer wanted to," that's just silly.
Another example from Star Wars: There was no good reason to add Hayden Christensen's ghost to the end of Return of the Jedi, or add a Jar-Jar cheer of "Wee-sa free!" to the end of Return of the Jedi, or to give Sarlacc a beaked mouth, or to go out of the way to make it look like Han shot first.
Also, the "morning report" song added into The Lion King just sucks.