This is what I'm talking about; how our players are going to react to 4-3-3 and share defensively in it. It sounds more secure for example when our midfield trident have the flexibility to roam in the midfield with both our wing forwards helping them out defensively. This would alleviate the strain which the midfield players will face plus make us more solid defensively. The unreliable point is the two wing forwards, I don't mean generally in the formation itself but the available players in our roster who will possibly take that role; Del Piero and Iaquinta. I'm certainly not expecting both of them to aid the midfield in defending, just one of them will be enough according to the match situation. But I disagree with you about Del Piero, I don't think he'll be able to do his best, at least when it comes to his defensive roles, also Iaquinta doesn't share effectively in defending from what I watched. That's why I prefer to place Salihamdizic instead of Iaquinta. Anyways, it's all about predictions, we'll see what will happen in the summer camp.
The best example for 4-3-3 that appeal to my liking is the one used by Murinho's Chelsea in the past few seasons, even before Essien joined them. They had a hell of a midfield that didn't require essential defending efforts from the attack line. Although, they lacked creative skills in their three midfielders, but they compensated for that by their pace, solidity, hardworking and harmony.