Pro (for the fans): he’s an unknown quantity. We really don’t know how he’ll peform, but he could be really good or he flop spectacularly – and that makes him exciting.
Pro (for the team): he brings in so much publicity, sponsors must love him. He’s certainly the best news story Lotus/Renault have had in a while, what with Kubica’s injury, the Lotus court case, firing a driver mid-season, and falling from earlier podiums into deep midfield over the 2011 season.
Con (for the team): given that they failed to stay the course last season, what Lotus/Renault really need is staying power. Someone who can press the flesh and put in the hard yards on track, even (especially!) when the car’s faltering. Someone who – unlike Heidfeld, for example – is willing to take the time to build a strong relationship with his team. Is Raikonnen really that man?
Con (for the fans): it’s getting so it’s easier to come out of retirement than to break into F1! Next they’ll bring back Villeneuve and Coulthard, and fire Perez and Di Resta…