[Bakha]

I can tell you that on Armageddon (when I staffed actively at least), the players really wanted that sort of interaction. Most individual staff members would be running a variety of plotlines involving their clans and groups of players. Staffers were usually responsible for playing a variety of NPCs, providing room echoes/atmosphere, and things of that nature. Probably one of the neatest parts of Armageddon (and other games like it) is that it's often hard, from a player's perspective, to know when you're interacting with another player or something animated by a staff member. You don't know if your "boss" in a clan is a staff-run NPC or a player-run PC. You don't know if that thug tracking your PC through the alleys is a PC or NPC. On Armageddon, the most common staff member is titled "Storyteller" and that's pretty much their job. Create stories, provide back up for players who are trying to create stories, and tie various plots together when possible with gentle nudges.

I know that there was a recent push on Armageddon, from what I can gather on the discussion boards at least, to try to push the players to generate more plots and have more control over the game world. It was felt that they're often too reliant on staff members to keep things moving. The players, on the other hand, complained that they felt like it was impossible to make anything happen without the staff stepping in and changing things. The desire was to balance the two out to empower the players to initiate plots and have the staff make the world react accordingly.

Anyway, back to your first question: as a player (before staffing) on Armageddon, I completely popped wood every time a staffer would get involved in what I was doing. Absolutely loved it.