There is an answer to that and we saw it last season: 4-4-2.
Wenger even mentioned it in relation to Sanchez.
I totally agree. I've been dreaming of a 4-4-2 with Theo and a target man (Giroud?) playing up front for years. But our midfield would be even more overrun than usual by the top teams. We'll see.
Wenger only played 4-4-2 as a panic button of sorts against the minnows and is suicidal against a Chelsea. We already win against the lower teams pretty handily, not sure 4-4-2 would solve our problems that much. but it would give Giroud more of a role.