One of the reason for high trust on bitcoin is that the bitcoin owner Satoshi identity is hidden. If all of sudden Satoshi come in the public and his identity is revealed, do you think it will have a bad impact on the bitcoin price and it can dump? Or do you think that bitcoin price will pump on this revelation? Mind you that i am talking about the real satoshi, not the fake ones claiming themselves to be satoshi.
No one really knows until it would happen but to know that Satoshis isnt even known after a decade then lets presume that he wont really be having any plans for showing himself on public.
Also we dont even know if he's still alive or long time dead and this had been always a mystery when it comes to his identity.We do keep on speculating and guessing.
Speaking for the question whether bitcoin pump or dumps then it would be always on communities decision on how they would react if the creator would surfaced out.