He notices danger for one thing and tries to snuff it out. Doesn't give away as many dangerous freekicks, or put his elbows in people's faces. He's a better passer and more mobile.
I think you are talking some nonsense here about Schneiderlin or you haven't notice that Schneiderlin doesn't do the stuff you mentioned.
Firstly, he doesn't notices danger at all. He was clearly ball watching when we conceded a goal against Arsenal this season.
I remember the Chelsea game last season when we had the 1-0 lead and were under counter attacked, Schneiderlin was caught jogging instead of running to drop back and we end up conceded a goal from that counter attack. Some of the goals that we conceded last season actually came from his errors.
Second, doesn't put an elbow on people's face has nothing to do with being a good holding midfielder
Third, better passer? Both players are poor with their passing ability. I thought everyone at red cafe agree that Schneiderlin's main weakness is actually his passing.
And the last one is being more mobile doesn't make you a better holding midfielder. Being mobile is more suitable for box to box not a holding midfielder.
Can't we just admit that both Schneiderlin and Fellaini are equally poor? The main reason why Fellaini is ahead of Schneiderlin because of him being more useful for set pieces and Fellaini was performing well at the start of season while Schneiderlin failed to impress Mourinho when he was given a chance in Europa League and cup games.