I know I certainly would be after the crap that has gone on at RBR this year and their blatant support of MV as their favoured driver, even though DR has brought home far more points and in my opinion been the better driver.
RBR say they are waiting for 'his' decision, but clearly their best and final offer is on the table and it likely doesn't reflect his achievements within the team. At least they are willing to wait beyond the Christmas break to ask him to commit.
Both Kimi and Bottas have only inked 1 year extensions in their contracts, so both those seats are potentially open. Neither one likes to leave contracts to the last second, so if I was Daniel's management, I would get started on talks with them both.