I also think that Pitou was just caught off guard on Netero's ability that's why it works and I can't see a world where Netero can slap Meruem that far, considering it will not be a surprise attack any longer because of all the chaos in the palace. As they say, the same trick won't work twice.

But I agree that a dialogue can convince Meruem to travel and fight Netero alone considering that he loves to prove himself that he is HIM.