This is a tough call for Force India. Personally I think they should discount Liuzzi, he’s done almost nothing of note in his fairly substantial F1 career to date.
I’m a big Sutil fan. I know he’s not top drawer, but I think he’s proven to be a decent driver over the course of the last 4 years at the team, and on his day he is a match for anyone. I think people tend to forget how impressive he was at times in 2010- it was only in the second half of the season that he tailed off, and was overtaken by Schumacher and Barrichello in the drivers standings. He’s a good mix of speed, experience and money!
So then it comes down to di Resta and Hulkenberg. Presumably this all boils down to a question of Mercedes’ love: whoever Norbert Haug puts his faith in as Schumacher’s long term successor will get the nod. I suspect Hulkenberg is the more talented of the two, but it’s hard to tell given how little experience di Resta has had in single seaters in recent years.
And even if they are completely equal, don’t forget that Hulkenberg is German- and we all know how much that floats Mercedes’ boat!