Great idea as well as tossing granades back, both features should be implemented. It is quite hard to pickup granade size object and takes time, laying over granade is much faster. Make both options available so it will be players choice is he heroically laying over granade or covardly trying to throw granade away, succesfully throw back would be heroic, but failing to do it is covardly
Though no points awarder when sacrificing your self, but points would be added if you could toss granade back succesfully, only enemy kills should score points.