Nothing will replace it. There is nothing in the current OU tier than can single handedly bring you from 5 - 2, to 2 - 0, as somebody already pointed out.
Finally, I can use some decent teams.
That's a pretty ridiculous statement. In fact, there are many Pokemon who do that better than Garchomp because if the opponent has five Pokemon on their team, odds are that they'll have something faster that can revenge-kill, which is more difficult to say about Lucario, Yanmega, Salamence, and Gyarados.