McCully is an impatient man. He will not say so publicly. But those close to him reckon he is not so happy with the way regime change is being managed. He has a bit of a reputation as a "seagull minister", a frequent-flyer who when he gets back to base, "squawks loudly, poops all over everyone then flies away again" - as one rather bruised diplomat describes him.
This may or may not be justified.
What it is fair to say is that McCully does not tolerate poor performance. This was obvious during a United States New Zealand Partnership forum in Washington in 2009.
The speech Mfat served up was fundamentally a joke. One of those tick-box affairs that looked like it had been written by a junior officer with no appreciation of diplomatic subtleties, let alone the very messages that McCully wanted to send the US on the approach National would bring to strengthening and developing that prime relationship.
McCully rewrote the speech, working long into the night after taking soundings from the New Zealand delegation. John Key was also frustrated when he was presented with a draft speech for his first international outing at Apec just days after being elected Prime Minister.
Key long ago learned to value Mfat.
But while McCully strongly appreciates the strength of New Zealand diplomacy - which has spawned first-class international diplomats such as Tim Groser, now Trade Minister, trade specialist Crawford Falconer and climate specialist Adrian Macey - he is insistent on change.
The April speech showed McCully wanted more Gen-Xs appointed as ambassadors (rather than baby-boomers); more specialists (particularly in Pacific affairs); more partnerships to deliver New Zealand aid; some European missions closed; and New Zealand's presence boosted in fast-growing economies such as China, India and Brazil.
"My job is to enhance New Zealanders' interests overseas, not keep the [diplomatic] union happy," he said then.
What McCully wants he usually gets. But he did also use his own tentacles to dig deep into the ministry and ensure that talented younger diplomats such as Taha Macpherson, Reuben Levermore, Tony Lynch, and Vangelis Vitalis secured top ambassadorial jobs.
That these men (only a few women have been appointed to ambassadorial roles under this Government) are in their late 30s or nudging 40, is a plus. They are all energetic and excited to be in charge of a post during a time when McCully is refocusing New Zealand's external representation.
The effect of the Mfat restructuring is to scrap the "foreign service". Diplomats are no longer assured of a job for life. The rotational system will go. Family allowances are being stripped.
If diplomats who return from postings do not secure a comparable role back at HQ, they will basically be shown the door.
It is change at its most brutal and facile; particularly, the risible advice tendered by so-called HR specialists that redundant diplomats should turn to pets for unconditional love.
When Allen was parachuted into Mfat he was viewed as bringing fresh eyes to the role. Many diplomats appreciated his focus on developing a necessary strategic vision to ensure Mfat evolved its own "statecraft for the 21st century" (to purloin Hillary Clinton's phrase).
But within the ranks, Mfat insiders are saying it seems more like Allen was brought in to "do a job on Mfat" rather than "a job".
McCully does urgently need to disabuse the ministry of this notion.
Both he and Key have indicated the proposed restructuring plan is not cast in stone. And how does he now "send the love" without being seen to further undercut Allen?