I would really like to see harsher penalties for those exiting instances (typically do to the presence of a new player).

Voluntary exits from instances should have increasing penalties based on frequency; the first time within a certain time period should trigger the 15min delay it currently does, but the second should scale up to maybe 30-45 minutes, and the third should be SEVERE, along the lines of 6 hours or so, to sharply discourage this sort of behaviour.

The hard versions of the primal fights, for instance, are rife with this sort of crap, and it creates a very unwelcoming atmosphere for people just hitting level 50.