First of all, Bonus Potential Cubes should be offered in the Reward Point shop, as otherwise free to play players are either locked behind buying Maple Points in the Meso Market, or not having access to the Bonus Potential system at all.
Secondly, other servers have the ability to sell Master Craftman's Cubes, Meister Cubes, Red Cubes, Black Cubes, Bonus Potential Cubes and so on. I know that they got locked because of botters, but our Flames are tradeable, and from what I can see, botters don't really affect the market of Flames. Why am I forced to use Meister/Master Craftman Cubes before their expire when other servers can just sell them in the Auction House incase players don't need them?
As for Reds/Black/B-Pots - if the problem of locking NX is because of the ability to ask for a Refund from Paypal, just allow that option to Prepaid NX. That way more people would have a reason to buy NX - as they'd have more options to sell NX without breaking the Terms of Service, and free to play players would have access to cubes in larger quantities. Like the previously topic, cash cubes are tradeable on every other server but ours. With some safety methods, both Nexon and players would benefit from implenting said changes.