Nah. They're done. They've held the throne due to Tywin micromanaging their every move. He's dead.
Cersei is a moron, Jaime is basically useless at this point, Tommen is a little boy, Tyrion is gone. Joffrey is dead. Unless they introduce a fukk ton of new Lannisters next season, they're done. And even if they do that, the entire House has been gutted. Let's keep it real here, nobody is watching their arcs for Cersei, or Tommen. Tywin and Tyrion are the main draws, one is dead and the other don't give a fukk about the rest of his family.
Fred.
The salient point here is that they hold the throne. You can say they are done all you want, but until someone takes the throne from them they are the top lions. Next season we will probably see things start to crumble with Cersei running wild using a cyborg mountain to violate people and Dorne getting some revenge, but I just don't see who is in a position to outright take the throne from them.