Even if it had more open paths, it wouldn't be a Metrovania. The term has lost all meaning. Basically, the term people are looking for is 2D Action/Platformers. Which all the games (and Metrovanias) fall under. But that term doesn't roll off the tongue. So people started using Metrovania to refer to all 2D Action/Platformers. And only purists know the difference.
Dust is closest to a game like Muramasa. Which Muramasa is based on games like Legend of Kage and Odin Sphere. All of these are 2D Action/Platformers. But none of them are Metrovanias.
