"Sona has no counterplay"
is too tanky to focus with a warmogs and tanks stats. Heals arent aimed.
point and click turns her adc into a god and point and click peels you.
Her hard cc is knockups so tenacity is useless. Point and click shield like Lulu. Other than dodge the tornado no counterplay.
I know tank supports are really good atm but point is Sona is less obnoxious to play against and has more counterplay as someone who can be focused. Atleast if she saves herself with ult it can be a waste due to its impact and long cooldown, Lulu and Janna have peel on basics and Soraka can make herself tanky.
Turning Sonas Q into a skillshot is just taking variety from the game. There isnt any more countplay to auto attacks. Sona can actually be bursted down, she is not as safe as other enchanters.