Scaling of certain roles

Now I know this is gonna be a really controversial topic, but I feel as if the scaling of certain roles should be reduced. For example, mages like sona who are traditionally support. It makes zero sense how sona's damage scale , along with soraka its pretty op when the support is one shotting you. Also tanks like garen, why is it that garen can me pretty much to death, I feel as if their attributes and power scaling should correspond with what their actual purpose as a champion is. Give me your opinions i'd like to see what others think about it.