Many people have asked for a buff to these set pieces and aside from people who want it for their apparel or collection, these sets usually collect dust. The Azure Guardian Set is outclassed by various things, Wolver, Jelly, you name it where-as the Aegis is easily outclassed by other shields such as the Barbarous Thorn Shield, Ironmight Plate Shield, and the Royal Jelly Shield.
Rather than giving these small buffs I believe that the Cobalt Set along with the Defender line were always meant to be the "cheap alternative to better armor." In other words it's the "Easiest to get but is a horrible choice in the end" or "Run of the mill."
Basically, my suggestion on this part is to cut down either the Crafting Price or the Orb requirement cost. Already the recipes are handed to players easily and they were always the niche of easy-to-obtain equipment it may help push players a bit more or even a slight more incentive to get this armor just for the fact that it is indeed easier to obtain but much harder to deal with later game.
One of the best suggestions so far as the Cobalt set is meant to be a Starter set. Easy to get and has basic stats but horrible at the end game.