The only difficulty with this is a listing fee punishes poor individuals who want to try and sell the big bank items and barely effects those who are already absurdly wealthy. I feel like this would have had to have been implemented from the start to really work properly, as you've already got a select few on each server with more gil than they know what to do with.

I do agree that it's a great way to make people think more about removing an item and relisting it to adjust the price, though.