I read something a couple of months back that did briefly question whether Pfizer had simply been too conservative on their dosage levels. While I haven't read anything lately it could be a key thing going forward, and necessitating a 3rd Pfizer dose for everybody who has had Pfizer.
As one of only a handful of countries that are 100% Pfizer, the shortcomings of the vaccine could be of serious concern for us and really do show the shortcomings of adopting the strategy we did.
They'd have taken into account ability to produce vaccine in quantity when setting dose levels in the trials. Same as the interval between doses, VE fairly well shown to improve with a longer interval, but you can't test everything is a stage III trial.
Moderna haven't been able to deliver many doses outside the US. So we'd have been S.O.L.
The "shortcomings" are relative. Most of the world who are lucky enough to be vaccinated aren't getting (the better) mRNA vaccines at all.
Is Pfizer at 9-12-15 months better than AZ? Only time will tell, but some tentative data has been showing for months that for elderly that AZ could well be a far better vaccine, and for the rest of is that could well end up being the case as well if we don't have boosters.