Yes it is a great idea. I did this awhile back and it was very freeing. I gave a bunch of fabric and scraps away that was in the "second tier" and I dont miss them one bit. Fact is that I was not going to use them.
Like he said the key is to sort and get rid of them ASAP. Then you can look at the fabrics you have and really invision the projects.
I am about ready to do it again.