So I brewed an american wheat, and i figured since it isn't gunna be clear anyway i went ahead and let the sparge go real fast, didn't worry about the grain bed filtering anything, and didn't vorlauf at all. Fast forward to now and it still tastes pretty good, but you can definately tell there's something off. It has a harsh, husky aftertaste with what seems like more than 13.5 IBU's worth of bitterness, but you don't get that extra bitterness until after you swallow. The initial sip tastes just fine.
I'm a chef by trade, so naturally I find myself testing all of the brewing old wive's tales, because when it comes to cooking most of the old wives tales are total false. Let me be the guy say, vorlauf is most definately necessary, along with patient sparging. Prost!