My thoughts have always been that the Balkans/Anatolia is the best borders for Byzantium. Annexing Armenia was likely a step in the wrong direction.
I have heard an argument that the consistent Arab raids which shifted the Anatolian economy away from agriculture and toward pastoralism created the perfect set up for the Turks. So perhaps any earlier cessation to the Arab raids will be important to keeping Anatolia strong against an inevitable Turkish incursion
Keeping Armenia as a buffer state is a prudent strategy, but the situation leading up to the the Battle of Manizikert was in no way inevitable. Under Empress Theodora previous Turkish raids were dealt with swiftly.
It was a combination of unimaginable stupidity on the part of the reigning Emperor Constantine X Doukas that led to the debacle. Not even the Angeloi as self-destructive, corrupt, and incompetent as they were would have done that. Not even Phokas would have done something like what Conistantine X did.
The imbecile chose to sit idly in the palace while his courtiers kept bringing in news of Turkish raids. He dissolved the 20k strong Armenian garrison in the face of an invasion into Armenia. He did it largely because he didn't want to cut back on his indulgent and opulent lifestyle in the capital. Its honestly a mystery why the man wasn't assassinated or forcefully deposed by anyone in the court. So many Emperors were blinded for much less. I know there was an assassination attempt in 1061 though by the dynatoi.
I could definitely see the imperial title evolving into something like a lifetime elected appointment, although that itself might be too much of an anachronism given the early POD
Not really. The Empire was an republican monarchy whereby the Emperor was acclaimed by the will of the "Senate and the people of Rome." In practice that meant the army. This had been the case for over a millennium, so that's not a very likely scenario.
I have heard an argument that the consistent Arab raids which shifted the Anatolian economy away from agriculture and toward pastoralism created the perfect set up for the Turks. So perhaps any earlier cessation to the Arab raids will be important to keeping Anatolia strong against an inevitable Turkish incursion
It was more because the wealthy nobles kept trying to consolidate more land under themselves and this led to them driving off peasant landowners. This sort of left Anatolia depopulated, though Anatolia was never really majority Islamic/Turkish until well after the fall of the Byzantine Empire. Even during the reign of Sultan Osman I, a good portion of his troops were made of Greeks and Armenians who either converted to Islam or preferred Turkish rule over the Latins.
The Byzantines had the opportunity to defeat the Turks numerous times though. I believe the last chance for any sort of reconquest would probably be in the early/mid 13th Century. Though Andronikos III's campaign in the 14th Century had he almost won, had the makings of recapturing most of the Greek lands in Western Anatolia.
Though if say Alexios Philanthropenos wasn't blinded he probably would have changed things drastically. The man was a very good general and even when elderly and blinded when news of his arrival reached the invading Turks, they fled in fear of him. Had his coup been successful you probably could have ended up with a Byzantine Majorian.