Very interesting thought, that I'm surprised I never considered given ow many cameras I have taken apart.
The main issue is that the thin, hard edge of the iris/leaf shutter is going to cause violent eddying which would slow charge flow into the intake.
The other issue is that this would require a center axis mounted fail metering rod that would have to extend either along the x or y axis of the bore in order to meter throughout iris opening. This means that there is little tuning to be done with a needle to manually sync with throttle position.
As you noted, this all comes at the price of complexity. So more complex and mutliple tuning hurtles probably would render this moot.
But a really cool idea in theory, noentheless.