Dean Hall has gone on to great success after doing a little mod called DayZ for Arma II. Work continues on the stand alone game using the Arma III engine, but it will have to go on without him after the end of the year.
Talking to Eurogamer, Dean said he's stepping away and starting a new company back in his home of New Zealand. He's talked with Bohemia Interactive already so there's no surprise there. The surprise is that he's dong it pretty quietly and giving up his baby to the current staff at Bohemia.
Now, there is some flexibility in the time he leaves so he could possibly stay a little longer, but he's got a few games that he wants to work on already with a new studio. It will still be in the multiplayer realm and in the survival genre, which he is fascinated by. Also, he says he'll still be active with the DayZ community, so that's good.
I know it must be hard to leave something you've created as well as passing it off to others to continue work on as I've done that a few times, but as a developer you have to do what you have to do to keep your mind engaged. It will be a few years probably before we hear or see what Dean has next on his plate. There's still plenty of time left for Dean to work his magic with DayZ though, but at least fans know that come next year, there will probably be a new person in charge of the game.