Let me step into the fire and say I think it was a good thing. Or at least it was not a bad thing...
There are many, many evil arab governments in the region. Mr Saddam was a particularly bad brand of evil. He spoke a big act, but he had provoked the attack on Kuwait, and I remember seeing this action as the act of a Hitler-type who had boldly threatened Israel. Saddam did fire rockets and missiles into Israel during the First Gulf war.
I am still of the belief that Iraq did have chemical weapons at some time, and while they never found enough to make a case, there were some chemical agents which were found. And it is also believed, by many in the intelligence agencies, that much of Iraqs chemical weapons ended up in Syria.
I never believed, nor do I think it was suggested, that the action in Iraq was a result of 9/11. We know that Iraq did not have any involvement with the planning or execution of the 9/11 terrorist attacks. But I do believe that there was credible intelligence that Iraq wanted to build and utilize chemical weapons.