@Riot Can You Elaborate on What's Wrong with Tank Items

A few days (a week maybe?) ago, you guys posted this on Reddit regarding what would come after the Assassin Update:

It's either tanks or divers. Tanks and tank itemization are in pretty dire need to looked at tbh so there is a pretty strong case for tanks to be next as well as divers.

What exactly do you guys believe is wrong with Tanks and Tank itemization? I'm not saying there is nothing wrong, but I would just like to know what YOU guys believe is wrong and what you might do to solve it.