New Gamemode : Passive Mixup

I was in a call the other day, and one of my friends hit me up with the question " what if Katarina had Annie's passive? " And I felt like it had to be in the Boards. A game mode where you pick a champion, but the passive you have is chosen randomly. Some champions that require their passives to even be playable such as Gnar or Sol will probably be disabled in this mode, but can you imagine the possibilities? If you're lucky, you could end up being Riven with Kennen's passive, or Vayne with Darius' passive. There are many possibilities, some broken, and some just down right ineffective, that's why I think in there mode there should be a purchasable item called the P-dice. It can be brought in the shop for 500 gold, and if used it changes the passive you currently have. Now this would probably be insanely hard to implement into the game, but I think it's a cool idea, and I wonder what you guys think too.