When Star Wars: The Force Awakens debuted my friend was saying the shape of the lightsaber was impractical, playing on the common misconception that the cross hilt in a sword is to block sliding blades (they are not, they provide a better grip, and another vector of attack). The iconic shape was open to be ridiculed across the web never-the-less.
One year down the line, I'm guessing there probably is some (Disney) extended universe lore about his saber, maybe clarifying the reason behind the different design.
So my question is, why did Kylo Ren use a crossguard design on his lightsaber, over the more traditional and common design?