I understand that MMORPGs are largely about retaining players (and keeping them paying) for as long as possible, but I have to say it is incredibly demoralizing to grind a single raid for months and still not have the desired equipment because the pieces you need simply will not drop from bosses.
"Raid coins" like the Manufactured Coin, Puppet Coin and Breach Coin are currently only used to purchase upgrade components for Tomestone Equipment, and I believe they would be a better feature if they had the secondary purpose of allowing the player to purchase equipment from Alliance Raids. Not only would this prevent them from becoming obsolete with the beginning of the next expansion, it would also act as a solid "bad luck protection" to prevent cases of someone playing the same dungeon a hundred times to obtain one specific piece of equipment, and burning themselves out from the game in the process.