In your post you said this is nothing new. In actuality it is somewhat new in that this is not a propaganda piece they can use to support themselves in the eyes of the North Koreans. They just sank a fucking ship and killed 46 sailors and injured more. There is probably not much more they can do to beg for war except maybe launch cross border attacks to kill more south Koreans.
This is not business as usual as you seem to assert. This is an escalation in aggression that is different form the North's usual shenanigans.