Greetings in that Divine and Most Precious Name of Our Lord and Savior Jesus Christ!
Nicea I was a debated Council.
Not really
?
You've no doubt heard of Pope St. Athanasius' five exiles, no? Athanasius contra mundi, Athanasius against the world? St. Jerome's famous quote "the world awoke and found itself Arian"?
Yes, really.
it became
the relative corner stone of all the jurisdictions
ALL the patriarchates were controlled by the Arians and their sympathizers.
interpretations were debated, but the Ecumenical legitimacy seemed rarely in question
yes, it was. Dozens of new creeds were written up to replace it, which is why the Fathers of the Second Ecumenical Council set their seal on it.
where as it was not until Justinian that the Chalcedon Council truly took on the kind of Ecumenical status it subsequently enjoyed.
It was explicitely accepted by all the patriarchates (except Armenia, which had a murky status). That wasn't in question until 30 years later.
Monotheletism never united anything, just created more schism.
In the long term, yes. In the short term, much of the political and ecclesiastical leadership of all the major jurisdictions and polities were finding mutual and diplomatic agreement.
No, Monotheletism was fought from the beginning, and greatly hampered the ability of the Emperor to rally the Christians against the Sassanids and then the Caliphs. It did find some non-Chalcedonians reconciling with the Emperor, only to lose the Orthodox.
It was not necessarily the soundness of the Monothelite doctrine I'm referring to
I should hope not, as Monothelite doctrine has no soundness in it.
so much as the temporary political unification which it stemmed from.
The henoticon had better success, let alone Chalcedon.
There were a lot of hand shakes and friendships established by the discussions, and the increase in schism really only came AFTER Emperor Heraclius' death.
No, Patriarch St. Sophronius made sure of that. Though, if you mean that the Emperor and EP abandoned their first formulation of monotheletism in the face of Pat. St. Sophronius, then I guess you can say that, but even then Rome and Jerusalem rejected Heracleus'
Ekthesis, and Heracleus rejected the heresy on his deathbed.
Of course the Orientals emphasize the miaphysis and therefore a miathelitism, which the Eastern camp found detestable, however, doctrinal disputes aside, the political personalities had come to a lot of consensus and agreements during their discussions. Personally, I feel it is the politics more so than the theologies which divided the Church, both during the Chalcedon debates and the Monothelite debates.. Politics are uglier then religion generally speaking 
Yes (except for the Monothelite debates).
God intends no schism.
Well, the reality of schism seems to speak for itself on this one.
No, it doesn't, but there is no shortage of those who will speak for it.