That list is not great for a club that are serious about challenging for the CL.
If you are looking for top level quality that is consistent, there are very few of our squad that are good enough for a top four side.
I would say that:
are definitely worth their place in our squad.
are good players but lack consistency which is important at the top level.
Ozil is a top quality player and our best midfielder but, for what ever reason, isn’t doing it on the pitch and if he can’t perform consistently then we have to get him off the wage bill.
Like you say, we’re desperate for at least couple of top defenders and we also need a DM and winger, assuming none of our best players leave.
If Arteta can get a CB to play alongside Saliba, a CM like Partey and maybe Courtinho on loan or Willian, then we will at least have a team that can at least compete for a top six place.