I have found that when using Warm & Natural batting my quilts were heavier if I FMQ'd them too much. (Imade a sampler quilt for my RV and it is too heavy to use on top of us, due to the batting and lots ofquilting in every block.
I have switched to Bamboo batting (I get on sale at JoAnn's) which is really soft and appears to be fluffier and softer after FMQ. I also like Hobb's wool--softer and fluffier as well. Trick is less FMQ makes for a softer quilt!.