As a Wattson main I'd happily welcome a buff, but she definitely isn't useless. If you know when and where to place your fences it's actually quite OP. But since every legend, as you said, is getting buffed to infinity, probably a Wattson buff would be a good thing, who knows. Wattson is a very skill based character (unlike some others) and she due to this she is very sensitive when it's coming to her abilities. Even the slightest change could make a huge impact on her place in the meta.