The pvp game changers like festival runes or tank rune hurt players and get them frustrated if they dont have them. Not everyone has been here from day 1 and you will alienate the new players we desperately need but cant find anymore. DB has made PVP very complex and difficult with these runes at our disposal, imagine if they don't have them? Make them available for purchase in an event shop. Make them appear only to players that don't have them like you currently do with the skins or make them available for purchase with money if you need a fundraiser. At least at that point, you've given people a chance to get what they missed because life got in the way of grinding tickets, pumpkins or candy canes.
In some cases, one might have been in a guild that didn't achieve max achievements a year ago and missed out on a good one.
I think this is a super important discussion, not for people to finish their collection, but for the future of the game itself.
Other runes to consider are the rare off stat runes like a double defense rune on a green or double health on a yellow.