Tbh, I don’t think that compensation is needed. That is like going to Amazon, buying something, then 6 months later demand a partial refund because they are running a sale on it. Amazon doesn’t need to compensate you for running a sale.
Just like the devs don’t need to compensate you for buyers remorse. That is in essence what is happening in this case. I don’t think that anyone is going to leave because of a sale on gems or a change to aquiring legends works.
Going to remind everyone that if you spent money, then you decided to take a risk. If it didn’t pay off and you have buyer’s remorse, then that is your fault. Not the dev’s.
If you buy gems say, 1 day before the sale, then it would be reasonable to have the devs refund you some of that money. Most stores will do this where you can return the product and buy it for a cheaper price. But asking for a refund on all your previous purchases is rediculous.