Comparing unupgraded cards with rares is "not valid"
The whole idea of packs in this thread went very different directions of course but from what I understood
it boils down to the usual "1 Rare, 2 uncommons, 3 commons"-thing ...
The problem is, that nobody mentions what should/will happen to the already existing ways to obtain cards.
Elements already has a system of very specific ways to get certain cards, and this system is not exactly
compatible with a pack-system, if the pack-system is implemented in a meaningful way.
What happens to the spins in the meantime? Will I still be able to win shards in the Arena?
Will FGs still pay out their cards upped? Can I still win a Nypmh in a tourney? Will I still get to buy
all the commons in the Bazaar?
If the answer to these questions is "yes" then sure, go ahead ... introduce as many packs as you want.
They would just be an extra chance to win rares but not really much more ...
However, if the idea is to have packs as more or less exclusive source of cards in general/certain cards,
then you are proposing to change Elements economics completely. Hours and hours of mindless and
meaningless grinding will be ahead just to afford another 10 packs to finally get that damned 6th SoSac ...
I don't find that very thrilling to be honest.