I genuinely feel Cesc is 'too English' for Barcelona.
Barcelona like to move forward en masse, a wall of blaugrauna that advances as a triangle playing pack so they can overwhelm the opposition with weight of numbers and attacking options.
When you're a Fabregas, looking for the defence spliting pass to the man on the shoulder of the last defender, your game can play against that. Fabregas will bank on his ability to play the ball forward when Barcelona don't have weight of numbers on their side, he'll back himself to put it on a plate for a runner even if that runner is alone and outnumbered. Having played with Henry in his heyday and Van Persie as he was hitting his peak Cesc appears to feel that players of the quality of Alexis, Villa, Pedro and Messi etc. should be able to run onto those kind of passes and convert. Fabregas doesn't have the conservatism of Xavi, he plays a lot of passes that if they don't come off mean the team surrendering possession and Barcelona's style militates against surrendering possession.
Because Cesc makes 'risky' passes by Barcelona standards they have pushed him into advanced positions, so he can take 'risks' in areas of the pitch that aren't so dangerous to the unit, but he doesn't thrive as a forward. Fabregas is a midfielder. Simple as. Fabregas might score goals when played as Messi or Iniesta's understudy but he isn't that kind of player. Cesc is a centre midfielder and that's where he thrives provided he has the outlets for his vision and passing ability to make the best of these. Barcelona's rigid and unbending adherence to the tiki taka template isn't bringing the best out of him. Had Cesc been thinking with his head and not his heart when he left Arsenal he would've gone to Madrid where the long passing of people like Xabi Alonso plays a key part of their counter attacks. Barca ain't set up for Cesc.