And this is the issue. It's easy to point out problems but more difficult to come up with solutions. There comes a time of course when you have to accept that a manager has taken a team as far as they can, and take the risk with someone else to try to attain an ultimate goal. But that risk needs to be approached sensibly. I think we as football fans can be tempted to believe that the next new thing will lead to the success we crave. But there is no way to assess the huge number of variables that are required for this to happen. By and large (bar a few exceptions) football success tends to be difficult, if not impossible to predict. Who before this season would have backed Alonso to be running away with the Bundesliga? Who predicted that our ex manager would be doing so well in the EPL? Many people were even writing Klopp off last season...its the unpredictablility that makes football so complelling. You only need to look at Manure and Chelsea to see how trying to chase the next high can come undone.
So with Arsenal the question has to be whether Arteta is showing the ability to improve. Is his judgment sound? Does he have the qualities likely to achieve success? I'd say that to a great extent, he has already shown this. And it would take a complete collapse this season (not failure to win anything) to justify not letting him have at least another season to try to win something big, IMO.