Most people think that using a blazer (or similar) profile vane will control your arrow better than a standard 4" vane, and that simply isn't true.
The reason the Blazers work is that they remove the front 2" of the vane close to the shaft. This part of the vane, being so close to the axis of the arrow and very often in the laminar air flow boundary around the shaft has little if any effect on the vane's ability to steer the arrow. 95% of the stabilizing effect of the vane comes from the rear 2" of the vane, and that area that is farthest from the shaft.
By removing the somewhat ineffective 2" off the front of the vane, you essentially increase your FOC over a standard vane and provide better stabilization.
That being said, if you can't get good broadhead flight with a 4" vane, then you most likely have a tuning problem that going to a different fletching will only mask.
You can get a pretty poorly tuned bow to shoot well using 4" feathers fletched with as much helical as you can get but in the end, you still have a poorly tuned bow.