Sandman for a long time has been a Spider-Man villain, as well as a prominent Fantastic Four villain as part of the Frightful Four. However, there was a period where Sandman went legit and became a superhero. It actually lasted nearly 20 years I think, and during this time he actually had a pretty good stint as a member of the Avengers (as one of the many former villains who were redeemed through the team). While it lasted a long time, the status quo eventually reverted itself when the Wizard used his mind control machine to make him bad again. It was stupid, and insulting, to undo all that character development. It also makes me wonder why no one ever tried to save Sandman from an in-universe standpoint, seeing as how others have been saved in the past.

Overall, it was neat. I sometimes lament that it couldn't stick because I like tangible change in comics when it works.