[Wolsh]

Silicium, отличная мысль!
FilteredSprite.as :

package  
{
	import flash.display.Sprite;
	public class FilteredSprite extends Sprite 
	{
		private var _filterArray:Array = [];
 
		public function FilteredSprite() 
		{
 
		}
 
		override public function set filters(value:Array):void
		{
			_filterArray = value;
			super.filters = value;
		}
 
		public function updateFilters():void
		{
			super.filters = _filterArray;
		}
	}
}

var mc:FilteredSprite = new FilteredSprite();
mc.graphics.beginFill(0x000000, 1);
mc.graphics.drawRect(0, 0, 200, 150);
addChild(mc);
mc.x = mc.y = 100;
var filtersArr:Array = [_shadow, _blur];
mc.filters = filtersArr;
 
_shadow.distance = 80;
mc.updateFilters(); // работает