It is well known that Arsene Wenger had offered Zlatan a trial in 2000. What happened in Zlatan's words were as follows:
"Arsene gave me the famous red and white jersey - the No 9 shirt with Ibrahimovic on it and I was so pleased I even posed for a picture wearing it. It was a fantastic moment for me. Arsenal had a great team then and here was an Arsenal shirt made just for me. So then I waited for him to convince me that I should join Arsenal. But he didn't even try. He never actually made me a serious offer, it was more, 'I want to see how good you are, what kind of player you are. Have a trial'. I couldn't believe it. I was like, 'No way, Zlatan doesn't do auditions'. I thought 'You either know me or you don't and if you don't know me you can't really want me'."
Ibrahimovic later joined Ajax and won league titles with AC Milan, Barcelona , Inter and PSG. But what if Zlatan had actually given a trial for Arsenal impressing Wenger to join Arsenal.
First of all we need to consider that Zlatan was a teenager at that point and wasn’t the badass we know him to be today (doesn’t mean he wasn’t a badass back then). Wenger is well known to be a disciplinarian and hence it is predictable that he would have frequent personality clashes with Zlatan, the end result being Zlatan being loaned out frequently or being transferred.
Assuming there’s no frequent clashes it would have been a completely different scenario for Arsenal as it is today. Since 2004-05 season, Arsenal have failed to win the EPL, even though they have finished in the top 4 regularly. Zlatan may have well proved to be the factor winning them the League.
After Henry left it was Van Persie who filled up his shoes and he indeed did a terrific job and there’s no doubt about that. But there has been a gradual decrease in goals scored over the years.
With Zlatan, Arsenal would have better finishing and higher intensity thus resulting in them achieving many laurels over the years.
In the worst case scenario, Zlatan would have been transferred quite quickly and his career and Arsenal’s performance over the years would have been the same as it is today. In the best case scenario Zlatan would be a little more disciplined and Arsenal would have a lot more success over the years.