No connection to Al Qaeda: yes... i didn't advance that, and i never thought Saddam had any such ties. Saddam was a Shi'ite, Al Qaeda is entirely Sunni. THAT connection was made in the French news in 2003 before the invasion.
Iraq had no WMD's upon the invasion. We knew that he had some before, which, along with the rest of his stuff (SCUDS et al.), like you said, were probably out of commission or in serious need of new launching systems. However, we knew he had the crap in the 90's, and we had cause to believe he still had some, which, for some reason justified the war to the administration and the rest of the senate. By that logic, we should have invaded dozens of countries before Iraq. Anyways.
Seriously, i understand it's speculation, but it's the most probable explanation for the convoys as well. Explain to me what you think was in those convoys, what would they have had reaosn to remove? We set out to invade to find WMD's. We don't find WMD's + large convoys leaving the country = what the heck else is supposed to have been in there? The fine and irreplaceable art was left in place and subsequently vandalized. Saddam and co obviously didn't leave with them. Gold and such was found en masse. The one thing he had to hide were weapons if anything.
Seriously, if you were to be on a search for something you think someone had, you see them passing something to a neighbor right before you show up, and then it isn't in his possession, i assume the only thing you think is "Hmm, well, i did see him move stuff before i got here, and there doesn't seem to be anything here now, and a lot of people have since confirmed that it isn't here... I suspect no foul play".
There was absolutely NO immediate threat from Saddam on the USA when we invaded. The urgency of the situation and "dire consequences" of inaction were entirely fictitious, and many of them outright lies. The link between Saddam and Al Qaeda was entirely made up, and who knows why we actually went there (revanchism/"prove daddy i can do something right"ism, oil, political/military influence in the region, whatever). However, we knew he had the junk. The amount was exaggerated, the threat it posed was exaggerated, but even what we KNEW he had, was not to be found...
No one is arguing the war was justified, even with WMD's present that we knew he had for decades.