I've gotten ribs tender with the 3-2-1 method, but they were mushy, probably foiling too long. You're supposed to unwrap them when you have "pull back" on the tips, but anyway....
I've been pleased just to smoke til they look good, then foil til tender with little or no liquid in the foil. I put the ribs back on the smoker at that point just to glaze and/or crisp up a little, not long at all, especially if the cooker is real hot.
You can use this method and cook them slow or fast. I believe the method I've used lately is referred by many here as the 2-1-10 min. method, cooking St. Louis ribs at about 300 degrees. I'm not an expert at this by no means, but I have learned this: The hotter you cook at, the smaller the window of doneness perfection. You can't just kick back and finish your beer like cooking low-n-slow.
Good luck with them next time!
Dave