The idea of letting players invite friends may be a good idea to make the playerbase grow, however I’m pretty disappointed by the quest that accompanies it, which requires 5 wins in Pandora for a second key. Here’s why :
The quest objective is tedious : win games is everyone’s objective in Pandora, and it’s already rewarded. I’d rather see a different objective, like play X treasures. And quests that include “Win game” in their objective can be easily done by some people in a single run, and take a few runs to achieve by others, depending on their level, draft, etc. Might be my own opinion, but I don’t like this type of quests at all (I much prefer those that give you an objective, like : play X cards of a color, or why not something even more creative than what you already propose)
The quest doesn’t feel rewarding to the player, as he has nothing to gain from it himself. Only can he invite one of his friends, granted he has a friend that wants to play Faeria. Otherwise, he’ll give it to a complete stranger in a thread of this forum, or not give it at all. At this point, you’d rather give away keys for free in the aforementioned thread, that would be the same end result.
Lastly, this quest cannot be removed/rerolled, so it forcibly takes a slot (you could easily discard the two previous points if it could be removed, so …). If you don’t like Pandora, you’re stuck with that quest you don’t want or need to do until God knows when, which is the nail in the coffin for me.