I know that people can locally moderate more than one board, it just looks dumb when there is one person moderating more than one board over a single, certain thing. It's a clutter to have my name plastered all over the top part of the forum, even under something that is official, and yet I am not official. The reason you do not see this as so bad is simply because I am doing a lot. If I acted like a normal person and divvied up responsibility amongst multiple people, then there would be more than one local moderators of different boards all for the sake of a simple, certain thing. And still, they would have nowhere to collaborate with themselves or with the moderation easily.
It is not as if ideas would not be run by the community, in fact, they are and have been. The Halloween Contest idea was essentially derived from what I had posted in Feedback and I owe Q.K. for the ideas of progressing it further. To have people working on the idea though and actually putting it through its paces so that there is an actual result rather than just a concept, you need people would are committed to working on it. And you're forgetting that the news really doesn't have to be run through the community each time an item pops up for it, rather, it just has to be actively updated to be viable on some level.
If you are worried about the staff getting run with ideas that are stupid, then having an events staff would at least make it so that the other staff would not have to sift through those ideas as they have other things to do. It someone had an idea, then the event staff could look into it and formulate its viability before it was proposed to a higher level.
And for some of your last example, not all ideas would be handled by the events staff, such as forum functionality. I don't know where you are going with that.