Let's head back into ERE history and assume Basil II dies sometime during his campaigns against the Bulgars, possibly from being wounded in a battle, possibly from an illness. Lacking for a direct heir, the imperial throne goes to his hedonist of a brother, Constantine VIII, much earlier than it did OTL.
OTL, Constantine got a few years as the sole regnant emperor but didn't have a ton of time to do much damage, mostly spending his time feasting, caving in to the noble families and otherwise infuriating people. The fact that he only lasted three years is a blessing.
What happens if we give him, say, fifteen or twenty years as sole emperor? Presumably real power in this situation would rest in the hands of the dynatoi, but how severely could a couple decades of an emperor as dubious in his talents and attitudes as this fellow actually damage the ERE? Are there competent enough people in place to basically rule around an emperor who doesn't have a lot to offer?