Over a week ago, I collected the data I said I was going to look at last time. I finally had a chance to look at the data (startup times with and without add-ons for two profiles on the latest version of 3.6), and my hypothesis was not verified. That means it is back to the drawing board for me. The graphs are not at all interesting, so I am not going to post them. At this point, I think the goal is officially at risk. With the profiles we got, I am not even seeing slow startups with cold startup. It is hard to diagnose a problem you cannot reproduce, sadly.
Next Step
Next week I am going to sync up with limi and get some contact information from the people that sent these profiles to us. We are going to have to do some remote debugging to see why they see such slow startup times.
News on the Past
Paul is feverishly working on a solution to make session restore not kill us on startup. He even has some test builds which you can download and test, but these are experimental. You should make a copy of your profile as a backup when using this test build in case things go boom.