I like the prices personally but what I have heard of is that you don't really earn more if you get to the maximum material or even if you go up from copper to tin. sure you earn more because you have to pay more but you don't earn any more than if you used copper.
Also im hoping there's plans for making the swords more...lets say appealing. getting to the next material is basically only changing their standard color. Would be cool if the color was more shiny than a simple paint.net fill color.