I have never dismantled an entire quilt, but I sure have done my fair share of seam ripping in my years of sewing.
If I ever made a blah quilt, or a quilt that I looked at when finshed, thought to myself "what was I thinking", I would donate it and make another one that was more appealing to my eye. I'm a firm believer in that not all of us have the same eye for color or taste in quilts, so even if I feel "blah" or "what was I thinking" about a quilt, there is someone out there that will like it.