The phrase "unnecessary remake" means a new version or adaptation of something (usually a movie or a song) that was not needed or requested, as the original was already good enough. Full definition
Then, there are the times it doesn't go so well — like Spike Lee's completely unnecessary remake of Park Chan - wook's South Korean revenge masterpiece Oldboy (although watching Josh Brolin chew the scenery for 104 minutes is not without its charm). (highsnobiety.com)
The Truth About Charlie is a bizarre, completely unnecessary remake. (abcnews.go.com)
Rooney Mara completely nails the role of Lisbeth Salander, and director David Fincher is no slouch either in this perhaps unnecessary remake of the Swedish thriller. (austinchronicle.com)