Bigger shoulder pads means a larger presence. It presents wealth, class, and some very handsome shoulders. Young women dragons have started donning these pads in hopes of matching up to male dragons in the beard-eat-beard world of the Superworm Exchange. Investing in colonies, building up an economy - things female dragons could never hope to achieve before these times. The shoulder pads are representative of a feminist bearded movement. You don't need to be a man to work for your food. It shows the women are not fearful, and can command just as well as any man! Gone are the days of the women basking at home making salads. They're out in the world, doing the same things as the men and taking charge of their future!
The question reminded me of 80's and 90's powersuits, with the huge shoulder pads for women. I have no idea what they're actually for. Most likely for display purposes.