Tenacity in my opinion, is a really under rated stat. It's very useful on tanks and just good in general. But there's not enough of it. You can get some from runes and a bit from Merc treads. But there is nothing more disheartening than using righteous glory just to be hit by a morgana snare and put in a 3 second time out. So my suggestion is that there could be more items that feel better to use. Dead man's plate for example. That momentum towards a champion and the sound it makes when you hit it is great. Makes you feel unstoppable. But then you are hit with a smattering of cc and killed. So maybe add tenacity to that and have it based off deadmans charge. Or have a new item that is kind of like an old Poppy ultimate, where you choose a target and all damage and cc from everyone else is reduced by 10. But if there were to be an increase of availability of tenacity, current items that do give it might need slight percent nerfs otherwise champions that DO build tenacity already aren't literally unstoppable. Let me know what you think of this in the replies, ty!