In my opinion it might be a good idea to "legalize" RMT by making Crysta tradeable in game.
This way players don't have to buy gil from illegal sources, taking away the means of existence for RMTs. Also by selling crysta in game, the community can determine the exchange rate of real money to gil.

This won't recover the economy on its own, but it might help to hold off illegal RMT activities if SE decides to improve the in game economy.

What do u think about it?