If it is my quilt, the quilt and batting requirements will dictate the quilting for me. If it is a client quilt, the clients wishes and budget get mixed into the equation.
If the piecing and fabrics are busy ornate quilting will not show anyways so I would do looser quilting like an all over or Panto. I freely admit I am a HUGE fan of dense, elaborate quilting ala Green Fairy or Angela Walters style, especially when there is a lot of negative space like a light colored background that reads solid. Usually I use dense quilting to get other motifs to pop like a trapunto style. So say I have a feather I want to emphasize, a lot of tight background fill will get that feather motif to pop right up off the surface. Same if you want to emphasize a bit of applique.
I agree that the batting will dictate stiffness more than density of quilting. I have seen art quilts very densely quilted, practically thread painted, but with wool batting that were very soft and drapey. I also agree thread choice will also make a huge difference.
So even though I love dense ornate quilting, I certainly won't use it on every quilt. The quilt and the batting decide density of quilting foremost.