The Byzantines lost their last holding in Italy, the city of Bari, in 1071, so giving them half of Italy is just not historical. Actually, they shouldn't even have any holdings in Asia Minor (the Turks made Nicea their capital around this time). It was only because of the first crusade that they managed to recapture Nicea and move in further inland. It would also be nice to place a strong Sicilian army in the vicinity of Durres (Dyrrachion) to represent that invasion of Robert Guiscard, which happened in 1081. It would definetely make a challenging early Byzantine game.
I know it's not historical. But i don't really care, the Byzantines are strong in the Early Era but are weaker in the other 2 campaigns. Plus with lots of spread out weakly defended territories they're not going to have an easy time in the Early Campaign.