Not sure if it has changed since the demo. But on my demo games the amount of chances they miss does get ridiculous sometimes. I mean id expect about half of one on ones to be scored but it's rare that that ratio is achieved.
I feel the game is very woolly on what it designate as a clear cut chance, but then that leads to the question; What is defined as a clear cut chance? I tend to ignore the CCC stat and judge each chance on its own, you often see that some CCC really arent all that clear cut, whereas some will be absolute sitters.
Its hard to make a comparison with the FM CCC's since the stat itself doesnt exist in real life. As for striker conversion rates i've dug up a few stats on the top finishers from last season (league goals only), these are all comparable to stats that can be found in game:
Edin Dzeko: 22 goals from 153 shots - 14.37% conversion rate; 70 shots on target 31.42% conversion rate
Mamadou Niang: 18 goals from 108 shots - 16.66% conversion rate; 42 shots on target 42.85% conversion rate
Wayne Rooney: 26 goals from 182 shots - 14.28% conversion rate; 58 shots on target 44.83% conversion rate
Didier Drogba: 31 goals from 178 shots - 17.41% conversion rate; 67 shots on target 50.81% conversion rate
Cristiano Ronaldo: 26 goals from 211 shots - 12.32% conversion rate; 94 shots on target 27.66% conversion rate
Gonzalo Higuaín: 27 goals from 198 shots - 13.63% conversion rate; 52 shots on target 51.92% conversion rate
David Villa: 21 goals from 139 shots - 15.10% conversion rate; 61 shots on target 34.43% conversion rate
Lionel Messi: 34 goals from 163 shots - 20.85% conversion rate; 86 shots on target 39.53% conversion rate
Antonio Di Natale: 29 goals from 152 shots - 19.08% conversion rate; 71 shots on target 40.85% conversion rate
Diego Milito: 22 goals from 86 shots - 25.58% conversion rate; 36 shots on target 61.11% conversion rate