Most of what can be said has been. But one thing I haven't seen in this thread is JP isn't overstaying, he is getting out when things are good and a new leader has a chance at success. Successful leaders (politics, business) almost ALWAYS stay too long in the job, to the major detriment of the organization.
e.g. Jack Welch, Jeff Immelt, JoePa, ORF, most of the current United States Senate.
JP apparently understands this and is not going to stay in the role forever as a desiccated corpse until it all falls apart. Good for him, one last smart move by a successful leader.