The 10x Cost which increases over time will kill the game even more.

I get that whales like it as they can easily afford them and the supply will stay low so they are more likely to keep their value. Value-extracting bots also like it because they can just keep them Soulbound and continue extracting value with just them as Summoners are included. However, everyone else gets screwed over along with the economy.

Many existing players who haven't gotten the set to where they wanted will be unable to complete it as the cost compared to the rewards just makes no sense whatsoever. They will further grow frustrated with the game driving them away. For new players it will be even worse as they will have no way to realistically ever get these cards while being up against older players who all can use them still in the soulbound state.

The game will be in a very unbalanced state where not only a couple specific cards but and entire set has an extreme low print rate while other cards have hundreds of thousands copies in circulation.

What I would do is the following:

• Unlock cost 2x (max 3x) the DEC burn rate + 1 Similar Type Card needs to be burned.
• Add a Glints Bonus % for players who don't use locked Reward cards (of this set).
• Keep the Unlock Price the same for the entire life cycle of the new set.
• Slowly increase the Glints bonus % each month so there is no upset.
• Once the new set goes out of print, no longer allow unlocking of the old set and give them starter cards status for those who own them so they can keep playing but not earn forever.

What this would do:

• Allow everyone to unlock their Soulbound cards over time at a reasonable price
• Create demand and burn a ton of old cards balancing the supply and increasing card prices
• Create a more level, affordable, and fair playing field for new players
• Still burn quite some DEC as many more cards would get unlocked
• Not increase the card supply more.
• Give cards that were paid for a fair advantage over locked soulbound cards.