I have kinda wondered about the explosions for a while tbh.
I mean the explosion should expand to the entire range of the weapon or object, otherwise it's like the player gets hit with an invisible force which makes no sense (well unless you're making a paranormal class game). It'd be nice if they had different explosion effects too like Blooming Flames, Dry Dust Explosion, or Radiation Explosion. (Just a few ideas

) A lot of things could be done with it. And I agree, the grenade explosions are really small compared to the actual blast radius :/