In the midfield, definitely...which is where a 4-2-3-1 is stacked. But then you've typically got Barry, who can't run and McCarthy who's allergic to 10+ yard passes, so now there's a void in the middle third and everyone farther up top has to come back to receive a pass. Either condense everything from the top down or coach/replace your midfield ammo.
You make a good point, but why is it Martinez can't see there's a problem?