What I don't get is that people moan that 3-4-3 is a defensive tactic?
Well yes it can be but its all how you play it, I think people see 3 atb and immediately think 5-2-3 but its not, we play our WB's very high up, or they think "no need for 3 CB's" but when your WB's play like wingers or are wingers like Saka, you're actually playing with 3 defenders, not 4 defenders like you do with 4 atb.
It also allows us to overload the flanks making it an offensive formation if done right, I also like that when we lose the ball we tend to mug it off the opposition quite quick because they literally can't break down our defense.
As we saw with Luiz, Arteta (being the deep mid he is) is a fan of this quarter back style playing out from the back and spraying the ball forward, when we do that we're already cutting out 2 CM's let alone if we fielded 3.
He may idealistically want 4-3-3 possession but ironically, everything that's important to him, the playing from deep and out from the back, the solid defense etc is all best done with a 3-4-3.
I think he needs to realise that and become his own man, stop trying to copy Pep and go his own way.
Pep does play out from the back but he doesn't have an obsession with Deep lying play makers and defense, he also prefers his possession higher up the pitch not possession through his defenders, there are some key differences, I think Arteta may have realised that tonight.