I prewash all my fabrics and wash and dry all my quilts as soon as the binding is on. They turn out crinkly but, the ones I use on my bed lays lay after a day or so. All of them crinkle a bit when washed and dried. Best way to get them flat is to do straight quilting. As with all aspects of quilting - different strokes for different folks. Not just one way to do anything.
I would like to see the heavily quilted quilts after they have been washed and dried.