What characters are you playing? As depending on your character you need to mix your abilities, guns, and melee. The point IS to mix it up. Some character like Harec and Konstantine rely on the guns more, while say Lycus with his shield and shotguns relies a bit more on melee.
Especially when facing an Antagonist that knows what they're doing. Grabs can beat a gun up close unless they just punch you in the face. I dunno I mix it up as I need to depending on my character.