If anything, investors will be encouraged to invest in China due to this news. Xi has been a stable leader for the country. This news simply means more of the same.
As a party dictatorship with routinely transitioned politicians, China's government has been fairly stable in recent times. Xi clearly isn't necessary in any regard, he's trying to make himself necessary. Hu Jintao was a stable leader that oversaw one of the fastest economic expansions in world history. He also wasn't necessary, in terms of remaining perpetually in power. Xi inherited that nicely built-up economic position. It's the policies that Xi follows/implements that will determine investor confidence, just as it was for Hu Jintao and Jiang Zemin (also a stable leader that didn't need to remain in power perpetually). Xi is properly replaceable like the others, insofar as he doesn't implement political changes that forcibly make him otherwise. The power move that Xi appears to be going for, is all down to his personality, rather than necessity, which is in stark contrast with the prior two Presidents.
- The risk that a stable leader with increasingly unlimited power will lead to stagnation, deep corruption, or war.
- The risk that a disruptive leader emerges after Xi and is not countered in time by government mechanisms (e.g. internal elections within the party).
Historic consensus seems to be that the former is the bigger danger, which is why even the CCP previously put a limit on presidential terms.
It's more about an institution vs a single man.