This is my point.
People tend to make sweeping and definite judgements about people and ability. "He's not good enough", "He'll never win a trophy" etc. "Good" isn't intrinsic, what defines the parameter of "good"? The reality is people need time to implement ideas and get people to buy in to the cause.
People who work under a manager don't trust management, no matter what career or profession, management is usually the enemy to most because their interests are based upon what those above them want, and those above them want growth and profits, at the expense of their employees. All the best managers you've ever worked for are easy to talk to, good with people, listen, and completely remove the "us and them" divide.
What I'm saying about Arteta is, he may be "good enough" to manage a big team, he may have great tactical knowledge, the best in fact, better than Pep, but none of that matters if his players don't buy in to what he wants to do. I personally believe he doesn't have the man management skills to succeed, and he needs to become more humble if he's to ever get anyway, same as Lampard. Once you start blaming people and you lose the staff, you're finished.
So give Arteta 5 years to make mistakes and learn, build his own squad of people he likes and wants to work with, or get rid and give someone else the opportunity to do that. Either way, nothing at Arsenal is fixable in less than a 5 year period.