When shit hit the fan, you should've taken a mandatory trade fee right away, slightly below the 0.5 % of Bitcoin.de so people would still be enticed to use bitmarket. Perhaps 0.25% because you haven't implemented a rating system yet and there was no option for BUY offers for a quite some time.

I think you should still do it if someone is willing to help you out. It'll be tough though because now Bitmarket is quite burned reputation-wise, simply because people will fear to lose their coins. Not sure how you can regain that trust. People are still out there using the site thinking nothing is wrong deserve to be warned. If you won't do it, others probably will and you will lose even more customers. Best to take down the side and stop all trades asap, or freeze all trades or whatever - have a message up with link to the forum, email all customers and see if people are want Bitmarket to open again in a few days or weeks. Bitcoinica could have even pulled that off, but they are just total knobheads and lost even this opportunity for a re-launch. I'd say a couple weeks after the hack it would have still been accepted and at least offered hope that everyone would get their money back.