Why Not Have A Rioter Whose Job Is to Communicate Through the Boards?

It's expensive to hire people for a pretty trivial job like that

trivial

If it were a trivial job, the entire disciplines of Public Relations, Community Management, and Journalism would basically be worthless. Almost every single large game development company in the United States has Community Managers or a department that specifically focuses on community involvement and communication; they wouldn't do so unless it increased the value of their product or brand.

I'd rather see Ghostcrawler and Meddler and Ironstylus on here talking about stuff they're working on, rather than see "Person X" on here as a mediator.

This is actually kind of an amusing example to me, and I'll explain why. In a lot of these discussions, Ghostcrawler/Meddler/Ironstylus aren't even the people working directly on a given project. They are, functionally speaking, representatives of their given discipline, just like a Community Manager would be.

Here's the thing. Bad community management functions like what you mentioned, where the Community Managers are just mediators or act as a barrier between the playerbase and the developers. Good community management, on the other hand, is a system where the CMs are directly involved in certain projects as part of the team and are experts at helping to organize and disperse information.

As an example, let's say Riot HurgleBurgle is the Community Manager for the Boards. His job is to participate in meetings and design decisions that define the platform, advocating for players along the way and making sure everyone is informed to the best of his ability. He might also even host forum events or utilize other engagement techniques to ensure players feel involved in the process, maybe even write up things like AMA summaries or changelogs.

The key here is that everything I just mentioned is completely missing from the vast majority of interaction and can't feasibly be done by the developers simultaneously. This idea that Community Managers are just middlemen is really flawed, there is so much potential that Riot seems to be intentionally avoiding.

That's more like a hobby of a few Rioters.

As far as I'm aware, the job of QA analysts is more along the lines of being part of the development process start to finish, offering feedback and helping to resolve issues along the way.

Communicating with the community is generally either a Community Manager role or some other role with Community in the title, but at Riot that department is almost entirely focused on outreach rather than involvement.