Well -- Arvo always felt as a starring character, and a very realistic one. His feelings and behavior around losing the key was exactly the way most of us would feel and behave in a similar situation. Anyway, I'm going to play v0.58 so I can see the changes. ;)
As for Gudrun, I really didn't miss her at the first three days of the vn, but in any case, this is not my vn XD. Let's see what happen to her.