In the context of early war planesets, the A6M2 was in a minority as compared to the likes of the Ki-43, and other planes.
A6m2 served far more a minor part in early World War 2, more like an equal player. Prime example is the Tainan Air Group who flew out of Formosa to escort betties to Clark AF and Manila. Why did the Squad spawn so many aces? They could fly into combat where the Ki-27's couldn't make the trip.
There were 3 squadrons of A6m2s that flew out of Takao in support of the philippine invasion, Only 1 Ki-43 and Ki-27 squadron were stationed in Formosa.
As for Singapore, Kompong trach has 2 squadrons of Ki-43s and 1 squadron of Ki-27s.
Soc Trang had One squadron of A6m2s, as well as a detachment of A5m4 claude's that were not upgraded to A6m2s yet.. These were the Zeros used to escort (if necessary) the Betties and Nells out of Saigon to attack the British Fleet at Singapore.
Two full squadron of Ki-27's were stationed at Singora that flew Cap over the japanese landing force.
How could you possibly say the A6m2 played a minor part in the opening battles of ww2 when they served more then 50% of the capacity? Far as I see the opening battles, only the Ki-27 and A6m2 played a roll, Ki-27 on other hand were slowly being phased out but not entirely at the opening few months of WW2.
It was the Japanese navy's decision to use these a6m2 squadrons to gain experience in the opening months while carriers were being built, so they can later be transferred to ships with experience, however as the Tainan Air Group shows - no carrier was available and the Japanese needed combat pilots at Lae/Rubaul.
Ki-27s were pretty much stuck at Singora due to lack of range, they could keep CAP over some of Malaya like George Town and Medan for extreme distances, they were not useable for the Philippines invasion, so they were put at malaya.
If were going to say one of the planes is a minority, it would be the Ki-43 which served in a VERY limited capacity in the opening shots of WW2 in compared to the Ki-27 and A6m2.
Now don't get me wrong, those Ki-27s were being replaced at record pace by Ki-43s, however they still served in a very limited capacity due to numbers.