One story in today's Globe and Mail tells about a passing motorist who picked up four pax who had found their way to the adjacent highway. The motorist said, "They were dripping wet, and kept apologizing about my car [getting wet]. . . . Their brief cases and their bags were covered in mud."
Several other places reference people who were carrying their on-board baggage with them after leaving the a/c.
However quickly the evacuation took place, it is almost certain that it could have been quicker had all baggage been left behind. I hope that the investigative report will discuss this aspect of the evac.
While it is not difficult to understand why some/many people took their on-board luggage (seriousness of the situation may not have been immediately apparent to everyone, general mindset that an extra 5 seconds to take the bag won't make a difference, cabin crew having many other other things to do than insisting that everyone leave all bags, etc.), it would be useful indeed if better procedures were in place to reduce the likelihood of pax taking baggage during an evac.