I fully agree that the main role of a PM is the translation between business, engineering (and design) and its therefore a question of literacy not ability to execute. I think the more technically-literate a PM, the more they can absorb of the necessary communication (and trust and expectation setting) between stakeholders and the development team.

The less technically literate a PM, the more that communication (or trust) may suffer or will need to be supported by development directly. The weaker the dev team’s communication, the more critical it is for a PM to have a deeper literacy. Fortunately, at Pivotal Labs all our developers are highly competent communicators so non-technical PMs can thrive along side technical ones.

The same is true on the stakeholder to design communication too, though that language is easier to learn.