You are specifically talking about T5, which is only one part of Arlanda. There's not much to it, especially from a legacy perspective. In the old days you had the A pier and the B pier. (Pier is not proper English; I am transliterating the Swedish.....) You knew that everything 9 and above was the B pier and SAS pretty much only flew out of A. So from that perspective a map would be kind of silly. Also, if you went through A security then you would be right by the lounges. I think there is a sign for the lounges?

When they opened the F pier the security moved, although there is still a "charter" security over by the B pier in the old hall. Once you are through security then it's F on the right, i.e. non-Schengen and everything else on the left. For connections the signage looks quite clear to me.....