I really like the idea, but I’m concerned about soulbound cards. There are many accounts with single BCX soulbound summoners (and other soulbound cards). If these accounts queue up together, they’ll often end up fighting each other, which could easily drain the reward pool.
That said, giving utility to soulbound cards beyond a single max copy should still be a goal. However, I believe a better solution would be this:
Only allow fully maxed copies of soulbound cards to be used. This would drastically reduce the potential for exploitation while still providing players with meaningful utility for soulbound cards beyond their first max copy.