I would say master-crafted is debatable, but Astorath at least has a definitive ruleset for his weapon, it's a S6 power weapon that forces enemies to reroll successful invulnerable saves.
I admit, I want MC to override that idea about the model's weapon having an impact, because I think it's bullsh*t that just because I modelled a guy with an axe due to liking how an axe looked, or because I modelled a guy without an axe (Dante) because I came up with something better, I'm now penalized.
At any rate, going by RAW, master crafted is a special weapon type and is classified as such alongside heavy, rapid fire, etc. I'm biased, but I think that qualifies the GE and Dante as having power weapons with additional special rules.