I've been talking to some friends about this, and I thought I'd run it by you guys. The real problem with the game, from my eyes, is the lack of money sinks. When FFXI started, all AH prices were extremely low, and the economy "worked". Players weren't having to think about buying gil. But because there is no way to drain all this money being generated from players, the total wealth slowly increased, which is exactly what leads to inflation in a game.
It's not that hard to think of ways of doing this, though they would have to be well designed. For instance, paying for storage (think up to like 300 items or so). Careful tuning could equalize the inflow and outflow of gil from the system, and certain one time events could be used to drain out large amounts of money for unexpected changes. To me, that's much more preferable than mass banning of accounts in order to drain the economy.
Once that is accomplished, all that is left is to fix systems that allow hoarding and undercutting of this nature. That though, is a topic that is incredibly sensitive in a live game environment where any change is immediately hated by a certain percentage of the population.
-Cliff