Alternative way to buy tenacity?

This is going to sound awkward but there are a lot of cases when enemy team has AA reliant champs (AD casters belong here too imo) and quite a lot of CC. For example top jungle adc and extra CC mid and support. So... there's the problem. Situation require extra armor and some aa reduction but freaking tenacity from Mercs cannot be ignored. Seriously may be you'll add some more interesting ways to get tenacity? I remember we had items like Zephyr in that case as boots replacement/just for extra tenacity if u have some other type of boots. I know this might cause Ninja Tabi spam spike but may be Tenacity item simply should be really specific? Like Zephyr. Not everyone could benefit from it. Or at least change freaking CC mechanic. Something like reduced duration if you got stunned more than twice in short period of time. Last 2 years this game feels like old DotA.