I see your point. After all even Theoderic got exasperated by the lingering Imperial loyalties of the Roman population and executed Boethius.
What I am trying to do is have the papacy a political tool of the Goths while not alienating the Roman population too much. One strategy may be to ensure that any future pope would be a native Roman or even Italian but no more Greeks.
This would be enough to ensure that the intellectual calibre of the papacy would be less than in OTL and of course may arouse a nascent nationalism, although I use that term cautiously. In any event in may make the Roman population side with the papacy as in OTL and because it would be more likely that the pope would be in disagreement with Constantinople more regularly and more deeply (even more than in OTL) this may well lead to a schism that has more permanent political overtones.
If this could be engineered then your point about Italy going its own separate road and coming to a compromise about the faith and the secular law may eventuate without an actual invasion. Indeed, it maybe that the popes would be even more independant and would not only refuse to comply with edicts from the east but even issue more of their own than in OTL and deepen any split between east and west.
We're quite in agreement on this. IMO, what would have been needed was another 2 generations without too much trouble. Barring the unfortunate imperial intervention, I do believe that Gothic Italy might have managed that: Theodoric had been able to set up marriage ties to all the other barbarian "kingdoms" in the west; the Vandals in Africa would not have any special reason to go for adventures (possibly some pirate raids, but nothing too much); the two most dangerous borders were Pannonia (protected by Longobards, who were under the Gothic influence) and Provence (but here even Wittigis was able to keep the Franks away; and there was always the opportunity of Visigothic support). Assuming that your POD works (Belisarius loosing a battle and his head in Africa), the backlash in the empire would likely to topple Justinian, and to put to sleep for a long time any ambition to reconquest the west; which would mean that Dalmatia would be secure, and that Byzantine troops on the Danube would anchor the Gothic eastern flank (ok, I'm pretty sure that whenever a migration comes, the Byzantines would bribe the barbarians to go toward Italy rather than in the Balkans: it would not be an alliance, just common interests, and in any case the border to protect would be shorter).
I would also anticipate that, once the news of the (failed) invasion of Africa reach Ravenna they should provoke an anti-Greek (but also anti-Catholic) reaction: something like the last years of Theodoric's reign, the African developments justifying and vindicating his late policy. Amalaswentha's demise should be on schedule (or even earlier): everyone is expecting a Greek fleet landing in Southern Italy from one day to the other (*), and a woman (in particular a woman who is known for "Greek" sympathies is not the right person on the throne). Quite likely that Wittigis once again gets the crown: there should be no butterfly yet, and a great bear of a king should look attractive to the Goth warriors.
It should be more interesting to see what happens in Rome: Silverius is a sure bet, even more so than in OTL (he was elected pope against the opposition of Vigilius, who was a Byzantine stooge). I would not really know if Silverius was a scoundrel (the alleged attempt to let the Goths in Rome from porta Asinaria, close to the Lateran, after which in OTL he was removed from the papacy and sent in exile to Lycia) or a saint (the catholic church canonised him not long after his death): what is certain however is that his puppeteers are in the Curia, not in Constantinople. These churchmen should see the need to appease the Goths, and therefore I would expect three things:
- better revenues for the crown (what better way to make a king happy?)
- bending backwards to show that they are not a Greek fifth column (possibly denouncing Byzantine meddling, and forcing some kind of wedge between east and west)
- going somehow beyond the council of Chalcedonia to try and find a common ground somehow between catholicism and arianism (which is pretty difficult, agreed: however, theologians are the right guys to prove the unprovable)
Overall, I can imagine churchmen and patricians wagging their lil tails and trying to look inoffensive and pro-Goths
Wittigis should reasonably try to arrange some kind of naval alliance with the Vandals, in order to make sure that there is not any repetition of the African adventure. I doubt that he's the guy to go for these fancy strategies: the best one might expect is that he can tame the Franks (and he should manage this at least). The second thing one might expect is that he's not becoming too bloody, and start a persecution (again, it takes a brain and a goal: Wittigis, beyond his desire to become king, lacked any other long-term plan).
I agree they would be rapidly absorbed. However, in the time it took the resulting population would be more 'Italian' in its outlook than Imperial. That is, the romantic longing for reincorporation into the Empire that was only shattered by the realities of the actual invasion and reoccupation itself, would dissipate and the influence of the Gothic notion of the separateness of the west would dominate political and social thinking.
If the Goths remain completely separate, I do not give them a very long life expectance. However, it is quite likely that the lures of civilization will work pretty well: maybe by 600 we might have a strong Gothic-Italian kingdom