Steve, I have the same experience with my wsm and are a big fan of using the water pan. Smoked two nice size packers low-n-slow last night for lunch today and the bark was much better than that from my last HH brisket just a few weeks back. That said, foiling probably gets a more evenly cooked product with more moisture and tenderness....at least more consistently. Still, the water pan most assuredly helps keep the meat from drying out and I wouldn't think of cooking ribs or brisket in my wsm without water unless foiling. If it's not broke though, why fix (foil) it?
If you're lookin' you ain't cookin', but if you're overcookin' you might start lookin'!