Arsenal are dealing with two problems, 1. The players are too average to compete at the highest level. 2. The coach lacks creativity and tactical ideas, he does not know how to motivate this young lad, he is only using them, he is not improving them. They need a good coach to turn things around at least fight for the Europa League spot.
When you say the highest level I think you going to far, when describing Arsenal, I don't think Arsenal can compete on an average level now, and that's what the should work on at the emirates, although I think they have exciting players, resources that Mikel arteta hasn't tapped yet, the had a very active transfer window unlike the Gunners in past seasons, but the players confidence are diminishing and I think a good coach can rekindle confidence of the players on Gunners roaster.