I have to agree with the OP. You get hit with a grenade, you should die, end of story. At least if you are not wearing flak armor. How to balance it? Make every grenade use resource points just like an actual grenade.
*shock*
Need more? Make its ammo replace the thrown grenade slot OR mine/c4 slot.
SOE takes the easy way out of everything instead of trying to maybe fix the actual problem with gameplay they just drop the damage and derp out a patch.