I really don't understand why people keep going on about Wenger.
Wenger isn't some never aging man. At some point he needed replacing, and that point was coming soon. Yes, there is a chance he could have got us into the top 4 with more spending, but we will never know, especially as his style was never to go out and spend £50m on players really bar the odd exception and his last year or two.
Wenger got us into the top 4 over and over, when the competition wasn't really that high. The level of the league in general was very poor for a long time while he was in charge, but he still did great things with what he had at his disposal. Saying that Arsenal fans were mad when Wenger got top 4, but now are begging for it, is such a basic and pointless argument. The top 4 now is filled with teams spending money, in fact the top 8 is. Look at Aston Villa recently, they spent more money than most teams and can barely get into the top half.
We needed a rebuild at some point, and United showed that even after winning the league it still takes a lot to replace a clubs structure. We were nowhere near that level when Wenger left, so it takes even more for us to do it.
If people want to think Arteta has done a bad job, then fair enough that's upto them. For me, he's won some silverware, over the past 12 months he's shown good consistency, and he has completely turned our squad around and is installing a style of play and some identity back to the club. His bad points are he did have a very bad 5 month spell, which I have seen he's taken some lessons from and is improving day by day with. And I was also very dubious about our attacking style and creation, but that seems to have improved lately (but we will see if this lasts or not).