Probably the master blender adds water because his job is to taste whisky the whole day I guess he first watches the liquor, next he smells it, then he tastes it, and finally... he spits it out.
On the other side of the supply chain are customers. A whisky enthusiast is supposed to be drinking just to enjoy that particular liquor, not to profesionally taste it.
From my view, if you feel your whisky 'needs water', then you should move to any other brand. You said taste was overwhelming. Ok, then you probably wanted a softer whisky. You can find a lot of them.
Interestingly enough I asked him whether the water was something that only a professional palate would require and he said no, that if you want to experience all the aromas and flavour notes in a whisky then he said you should drink it with water. He explained the science (I've paraphrased it on the previous page) and said that even an amateur palate should be able to ascertain more notes to the whisky once water is added.
The point with adding water is not to make a "softer" whisky as you mention, it is to experience all the flavour notes and aromas that are n that whisky. It certainly does not mean drowning it, he suggested a water ratio half to equal of the volume of whisky, any more he said and you are in danger of diluting to the point of affecting the flavour.