When was the list time Arsenal made a world-class signing? Never?
Before the summer nobody would have thought an absolute world-class player would have ever went to Arsenal over all the other clubs available in the world - now one has and another one almost went(Suarez).
Sure they have a long road left until they are anywhere near flawless, but that is not odd coming from a club that has a transfer record(Pre-Özil) of what United spent on Phil Jones/Ashley Young. So it is not odd that their squad has flaws.
I don't think you see the importance Özil has on Wengers future world-class signings. He will now have a much easier time getting any because he already got the first. It also shows that the club wants to be one of the best clubs in the world and I think a lot of people believe strongly in that intention right now.
Surely the question is whether they're better relatively speaking than the teams around them. Spurs have improved significantly, as have Liverpool, Chelsea and (maybe) City, where United have probably stayed the same. They are, for me, probably a better side than Spurs and Liverpool - but not the other three - the net result being that they're probably about where they were last year.
The fans want top players for one reason - to help them win things. I dont see that they're much, if any, closer to winning the league with Ozil than they were last year because of the improvements the sides around them have made.
This may be a new dawn for Arsenal, and they may go on to sign more world class players. Or this might purely be intended to appease the fans rather than actually mark any change in how he likes to do things - and still being happy with finishing 4th.
If he was serious about spending big and really challenging for the title he could have had Begovic (the best keeper in the league for me) Higuain, Ozil and maybe even Rooney or Suarez. That would have been a real statement, and would have given them a real chance of winning the league.
You're right that no squad is flawless - but when you have issues (esepcially in goal and upfront) you plug those gaps as soon as possible because that will cost you points. Wenger hasnt done that in my opinion - despite seemingly knowng that its an issue - hence the pursuit of Cesar and Suarez and Higuain.
The big question - if Arsenal finish 4th again, or even 3rd will the fans be happy? I suspect not, regardless of the signing of a top player in the summer.