Bitfinex should negotiate with hacker. Offer $10 million to return the stolen bitcoins and drop investigation.
Yeah, this could be done. However I think hackers will not accept the offer, because they prefer to earn much money instead of having to return all funds they have get and given only a small portion of the money to them. But it also depends on how bitfinex the hacker in the negotiation to seduce, hopefully this issue was quickly completed and running as before