Because his touch makes Kuyt look like Messi, positioning can make Luiz look like a God and his ball playing ability makes Skrtel look like Beckenbauer. He's basically surrounded by 9 players who are better going forwards than him, I'd rather him stick to his job and just defend. In my opinion.
He no doubt has massive potential, but I'd rather him work on making his defensive play top quality than add fancy parts to his play he simply isn't suited to.
And of course it's good that he can be versatile. In the same way Carrick
can play CB, but I wouldn't recognise him as a CB, nor will I properly recognise Jones as a CM, just a useful option.