As far as I understand, Manzikert was not a very total defeat - the majority of the Byzantine army emerged intact, and we have records of units involved at Manzikert fighting in other actions through Anatolia and beyond.
The problems which led to the loss of Anatolia for the Romans were twofold: the migrations of Turks, and the growing weakness of the Byzantine military establishment in the face of this. Manzikert was a symptom, not the underlying problem. While obviously a Byzantine victory at Manzikert would be beneficial, it would not be a panacea. In fact, it might well prevent any administrative reformation and lead to problems of a greater magnitude down the line. However, at least in the short term the Byzantines not having a crisis of leadership could only be a boon.