I wonder if you are using poly batting? I've used poly batting on only one quilt and I also quilted it quite densely and it is the stiffest one I've made. I used the poly batting for a particular reason, not related to quilting in general. It is a star block of the month from my guild and I had lots of ideas for the FMQ that I did. I use it on my bed and even though it is warm, it is not "snuggly" and I'm OK with that for this quilt. For the other quilts I make, I use Quilters Dream cotton batting which has a much nicer drape and snuggle factor even with some heavier quilting.