I'm not sure why 24h DMT as many requested hasn't been discussed, it would be nice to have transparency on the matter.
I can venture a guess that Nexon feels it's too lenient as limiting to 1-hours pressures the player more on making the best out of it; If that is the reason, I came upon an alternative idea for Reboot:
Daily Purchase Limit of Double Miracle Cubes
The premise is to change the current DMT system into the purchase of a limited amount of cubes from an event NPC daily over an arbitrary duration
It would greatly reduce the strain on the server as players are not only able to buy those cubes at once instead of spamming 1xCube pls at the cash shop but also at any time during the day
Make those cubes expire after 24h to pressure the players into using them instead of being able to save up for a future gear drop
I believe there are merits for the company such as
Further incentivize players into logging over the event duration
The ability to control how many Double Miracle Cubes players will be able to buy at most to limit their expected gains
Overall, players would be able to cube smoothly without having to sacrifice their schedules but they'll have to attend daily and have a limited amount of cubing possible.