ITTL there is the possibility of Regia Aeronautica bleeding white during 1940-1941. The are already cannon armed Hurricanes in Malta with more sceduled to come after the BoB. Malta has already its OTL radar stations. Besides, if we see cannon-armed fighters in Egypt and Greece in Q4 1940 they have the potential to seriously attrite the Italians. In OTL the RAF squadrons in Greece had Gladiators until February 1941. Granted that poor airfields and winter conditions will curtail the potential of cannon-armed monoplanes, but still I expect far greater Italian losses. Don't forget that every downed Italian airman will become a POW while RAF aviators would be provided with drinks from a grateful greek population. Between Malta, Egypt and Greece, lets say a dozen cannon-armed fighter squadrons may cause far greater Italian losses than in OTL. There is a golden opportunity that while the bulk of the Italian fighter force are Fiat CR.42s, the Italian pilot pool can be dealt a serious blow.
Another interesting aspect of the PAM is the far better condition of the Coastal Command. If a few squadrons can be moved in the Med, the Italian logistic apparatus can face a great challenge. In OTL a single Swordfish squadron in Malta could do little and the Italian had very very limited shipping losses. Have a few more anti-shipping squadrons flying from Malta, Egypt and Crete and there may be butterflies even in the deployment of the Africa Corps.
Lastly, in OTL the RAF seriously neglected the development of Crete as an operational base before the German attack. Maleme was half finished after 6 months and was built in uneven terrain in an exposed location. The OTL Chania International Airport is located in a far better position: Next to Suda Bay, with hills on the north providing an excellent flak location, with flat and well drained terrain. Furthermore, the small Heraklion civilian airfield was not properly developed. After 6 months, RAF had half finished 2 airfields in what Churchill had described as "a new Scapa". A semi-decent effort with a couple of engineer battalions (not to mention the friendly and accomodating local population) should have produced 3 proper airbases and a north-south road in those 6 months. The 3rd airfield I would put in Tympaki in the south, as Luftwaffe did in 1941-1942. It was an excellent location to provide air cover towards Cyrenaica and cover the approaches to Crete.