I though you didnt watch la liga, so how do you know this for a fact?
Ozil led the league with 19 assists last season and was one of the best players at Madrid. Have you considered that the problem is with Arsenal and not the player?
No one knows for sure how James, Griezmann, Mbappe, Lukaku,or any other player will play at a new club. That is an inherent risk that comes with all transfers. The best you can do his evaluate the players talent, skill sets, style etc and see how he will fit into your squad. Suarez was made a villainize so much he left the EPL, but is seems to be doing quite fine with Barcelona. Going by what you say about James, wouldnt be surprised if you would have been against United buying him back then.
If we let DDG go, the club needs to seek the best value in return, keeping in mind what the current needs of the team are. We have Pogba and have no need for Kroos, while there is a need for a creative attacking midfielder upfront. When Herrera, Rooney and Zlatan have the most assists, then there is something wrong, and, there is nothing to suggest any of Mata, Mikhi nor Griezmann is the solution.
We dont have to get James, particularly if there is better value to be found elsewhere, but that does not make him a bad player to get.