Ozil played until the break in last season as we played 4231 = he had a position he was suited to.
At the re-start we initially tried 433 before we moved to the 343 after the consecutive losses to MC & BHA. In both these formations there is no CAM, and in the 2 CM midfield the initial priority has been defensive cover to the hybrid back-line that has Tierney looking to get forward in the final 3rd despite supposedly playing as LCB in a back3.
At the time Ozil was not registered we were still playing 343, and this is the first PL game we have clearly changed formation since he was not registered. Despite using the 4231 in this game 'everyone' seems to be of the opinion Arteta's formation of choice is a 433, which does not use a CAM and has no position for Ozil.
To put it in simple terms it's not a case of Ozil being able/suited to play in any other position like Arteta/Cazorla/Rambo/Wilshere/KdB/Silva = he is more Riquelme in that he is a 1 position/role elite level specialist. For him to be selected not only do we need to change our shape we also need to carry him in order for him to be effective, which is also dependent upon him allowed to be a final 3rd only player.
The question then becomes is it worth it to do so for the limited time he has remaining at the club, after which we would need to start over once again? IMO at this point the answer is simply, no.