We did consider removing weekly withdrawal completely but we have a number of customers that are not active but have invested in recruiting a large number of referrals. They are the ones that typically have auto withdraw turned on and we don't feel it is right to keep changing the fee as they will not necessarily know it has happened. They are also the type of customer that is happy to pay 3000 sats a week for the convenience. For anyone that is actively using the site using the slow withdrawal makes much more sense.
Weekly withdrawals have no sense for me personally since the transaction fees, 0.00003000, would eat almost all my income there. I disabled auto withdraw several months ago and now I have 60k satoshis on my FreeBitco.in balance.
But I think you are doing the right thing keeping it because otherwise it would be unfair to those who invested their time (and maybe money even) in recruiting a large number of referrals.