The mentality and the way the players play would change drastically. Sanchez would be the single (main) outlet in the starting 11, with the rest of the team doing the hard work and creating.
It's the way Atletico play anyway, 4-2-2-2 with two narrow wingers. Griezmann with 20+goals, then Saul, Correa, Torres with like 6-8.
Ramsey/Wilshere/Ozil would get 6-8 goals, with Sanchez doing what Griezmann does. Impossible to say if it would work because we have Wenger and we'd have to go to a 4411/442, but that's what it would be in theory.
Either way, unless you have a manager who can motivate the life out of anyone, and have a manager who is hell bent on winning and nothing else, then you will fail regardless of the technical quality of the squad or the system they play.