I don't really know how to classify a good coach outside winning of trophies. Because outside trophies, we can't deny that Mikel Arteta has obviously transformed this Arsenal team into a force that's been reckoned and feared by other teams in both domestic league and European competitions. I think he Arteta just hasn't yet figured it out just like Pep Guardiola his mentor in winning trophies but am sure with time this trophyless seasons with arsenal under Arteta is going to be a thing of the pass.
Arsenal is now popularly known as “we’ll try again next season club” always next season, they Neva learn from their mistakes and Arteta is being unnecessarily stubborn towards signing a proper striker a no.9 how do you want to win a trophy without a nine not that you even have a proper striker playing as false 9. The game tonight so many crosses looking for who to make good use of it, so many missed chances. They did everything except getting the desired goals, I would expect the club management to ensure they get a proper striker in the transfer window and also they’re in need of a right wing forward to support Saka.
Well, anyone could call them any name they wish even "the league bottler club", but what matters foremost is that this Arsenal team has really been transformed by this very Arteta. They just have to keep trying and learning from their mistakes and in due time trophies could start flowing in just as it was with Manchester city, today they're UCL winners after many times of trials.
On account of a natural striker, I do agree with you about Arteta falling short on that area because it was very imperative he signed a striker in the January transfer window but for reasons personal to him he didn't and it has really cost him not just in the UCL but equally in he EPL against Liverpool. I believe he would see reasons to sign a proper top 9 now and even add to a right winger to peer with Saka to the left.