I am sure you are well aware.

Riot I can't help but notice that a new meta has arisen, which was intended AP carry supports such as Annie Brand Elise and I have even seen a Fizz and do to the overwhelming burst dmg of that meta Tanky supports with High CC get blown away so while adding more support options to experiment with AP Carry supports just overpower almost any Tank. I'm sure you can think of a better solution than I could however I propose that you increase the base MR of tanks in general because there are people including myself who use unconventional supports such as Nautilus however decrease the scaling on their MR. While I am sure there are better solutions I will leave that to you RIOT.