The Greeks against the Axis forces

First, to finegold: It is true that the greek victory was not some miracle, but for a careful observer (that did not exist at that time), it would be clear that the greek army was superior to the italian in quality, which is training (very basic, the italians had increased dramatically their numbers without providing enough training), morale, and in some cases even in equipment.
But still, the reasons you give are not the most primary, to my oppinion. The distance from Italy was a hinderance, however, as already stated by patrinos, the land infrastructure in Epirus and Albania was so poor (basically non-existant), that supplies had to be carried from the last train station at Ioannina to the front by mules, following mountain passages. That could take up to 3 days after the supplies were dispached for the soldiers to receive them. In fact, the Greeks had bigger problems with lack of ammunition and food than the Italians.
Also, as patrinos said, the preparation for fighting against the Italians was also poor, because the army was oriented against Bulgaria mainly. Unlike what many Italians seems to believe, there were practically no perpmanent defences on the Greek border with Albania until 1939, and then -as the italian danger appeared- only minor preparations were made at the ground. The Italians didn't find a prepared defence when they attacked Greece in October, and in fact, if they had made their plans better they could have won the war.

Patrine, the truth about the italian air force is that it was much bigger than the greek one, and appeared on the sky much more often than the greek. However, the time of the Grecoitalian war (Late autumn, winter, early spring) was the worst for an airforce, because the weather conditions were prohibiting operations. That's why a potentially important factor didn't play any role in this war.
Also, I don't think that in any way the greek soldiers lacked fighting spirit because they felt the Italians as 'brothers'. Perhaps they didn't hate them (as they would perhaps the 'traditional' enemies Bulgaria, Turkey etc), as they also didn't hate the Germans. But an invader is an invader. The Italians also had fighting spirit, but it was the course of the war that broke it.

A small part from the last interview with Professor Chris Woodhouse.