I'd say being a good communicator, an "effective communicator" has the most impact. Not only writing well, but being able to enter and participate in C-Suite strategy conversations as a peer. Not dominating, not "telling them the truth", but being a peer-wise political player in the political theater that actually runs the company. That is what comes after staff engineer, it's VP of technology, CTO and so forth. That game is all communications, but as a former developer your role is getting them to understand the realities of the tech teams' efforts and successes, and the required maintenance to see it continue.