I guess there are no hard and fast rules here, it must surely be down to the kind of quilt you are making and what kind of batting you use. Some require less quilting on account of the batting which does not migrate in the way others might. I happen to like a softer quilt hand quilted and made to to used, but a wall hanging might need to be stiffer and have plenty of texture in the decorative areas requiring more dense quilting. Every one to their own I think, I love to look at art quilts some of which have heavy quilting but I wouldn't be interested in making one, it is all down to the individual as I said and there are no rules.
Gal