First of all, the last word can kill in under 0.2 seconds. The average human reaction time is 0.25 seconds. Might as well be instant. Secondly, if the buffed weapons rather than nerfing them, this game would become another call of duty clone. Power creep would set in as weapons are continually buffed, and eventually the TTK would be the same as that of COD. That is why nerfing is almost always the better option if weapons are OP.