You misread my statement. I said that Fellaini cannot be given the responsibility to dictate play, of course, and partnering him with Mata or Rooney in midfield won't work as they won't be able to dictate play from midfield as well since they're more suited to playing in the final third, creating chances and scoring goals. Same goes for Januzaj and di Maria, and both have shown that they aren't able to control the game from central midfield. In short, we need Herrera in our team regardless of who plays as no one else is like him.
Also, Fellaini's only good midfield performance, for me, was against Chelsea during the first half. Against Man. City, he couldn't do much as he was forced to stay back, and in the rest of the matches, he was average (Crystal Palace) or below average (West Brom/Arsenal) though not as poor as he was at the first few matches of this season.
Yes, the deep-lying player builds from the back and starts off attacks, but it still needs someone to control the pace, tempo, and rhythm of the team. The deep-lying midfielder will be the outlet from the defence and start off attacks, but it still needs a midfielder who can play players into dangerous areas, control our build-up speed, tempo, and passing rhythm, and be the link between the attacking and defensive players. Bayern used the 4-1-4-1 last season, and whilst they did have Lahm starting off attacks, they still needed Kroos or Thiago to build up the attack and control the team's game.
We've missed that sort of a player from our midfield. Rooney and Mata tried to play this sort of a game, but both have shown themselves to be incapable for this. Rooney doesn't have the vision, movement, and mindset to be our playmaker, and the same goes for Mata, who has the guile to split defences and score goals but can't control our pace, tempo, and passing rhythm in midfield. We did well in the first half against Chelsea because Fellaini was very good in supporting Januzaj and allowing him to cut into the middle and play through passes. Against Man. City, we may have been comfortable in possession against Man. City, but on the attack, we created almost no chances and weren't able to get a flow to our game. Of course, the red card ruined it all for us before we could really settle. We saw what happened against Crystal Palace as well. We played too slowly, rigidly, and safely, allowing Crystal Palace to set themselves up, whilst the quality of our attacking players allowed us to be incisive on the attack and create chances. Same thing happened against Arsenal except we kept less possession.
I see you and I interpret "dictate play" differently. It seems as if you see it as a deep-lying player distributing the ball around and playing balls to attacking players, whilst I see it as something that Ozil, Wilshere, Silva, Nasri, Oscar, Fabregas, Iniesta, Xavi, etc., do: control the team's flow, rhythm, tempo, and build-up speed whilst also playing teammates into dangerous areas. It would be good if you could clarify how you define "dictating play".