I guess it's all down to personal opinions. It feels like many United fans are still scared by that Fellaini game against United. Personally, I don't remember Everton playing particularly outstanding. Fellaini had moments but was nowhere the best player in Everton, he was nowhere Baines, Cahill or Dustin. Schneiderlin not only bossed games, especially the City game, but was instrumental in a Soton team that pushed above their weight. All you need to do is to watch season reviews and see how good he was. It's easy to remember Fellaini because he scored against United and he's position closer to the opposition goal but Schneiderlin was stellar that season.
Just because a player has been mismanaged doesn't make him worse than the one getting game time ala Young and Di Maria. If we sold both of them to another manager I know which one I'd put my money on to perform better.
I hope Schneiderlin moves and prove that he's much better than this. Fellaini doesn't have anything to prove, he's not getting any better than this