ARN was a mess earlier in the morning too, due to problems with the baggage converyors. I had a 7:05 flight and arrived to long lines due to the check-in and baggage drops being understaffed. The baggage problems are no reason to be understaffed, but everything seemed to be a bit off in the arrivals hall.
Otherwise your experience fits what I have experienced with SK in the past (at least at ARN). We stopped flying the service to ORD because of delays/cancellations and numerous problems with the ground staff. With that being said, they were nice enough to give me an op up this time, which was great considering I had no time for breakfast due to the delays^.