I am part of a rules committee, so just unbanning or banning would have to be run through the entire committee not just me. If I was banning any card such as the example of Iona, I would then see if there are other cards that kinda/maybe/possibly do the same type of thing and see if they also would need banning.
I would suggest a few things like scrying if you are mulligan to 5 or lower. If per chance you are down that low to 5 cards or lower scrying the top card shouldn't be changing the outcome of a game by that much.
I also would suggest just seeing what white cards are busted in edh compared to the ones that just aren't broken and just let those ones that aren't broken into the game.