My group has an interesting system, but I can't really say for sure if it works the way I think it does. Those are purely my observations

1) People who participate in all rounds get packs
2) Each week different people get the packs
3) Each week people get different packs (ex. I got Legendary pack, so I will not get a legendary pack until I get Elite and Hero ones)

Well, in my opinion you should always prioritetize members who showed up to each and every one round. If there are any packs left afterwards, go ahead to other members :)