Well of course you'd have to trust the Overseer(DM)... the same as you would within Neverwinter Nights or the same as within a Dungeons&Dragons board game.  With great power comes great responsibility. 

The great part about the Overseer(DM) role is the game can continue without him watching every turn.  The players would not be aware when the Overseer(DM) would be present or making changes unless the Overseer desired to be recognized by sending messages to the players or playing the 3rd party merchants guild, etc., etc., .  Thus for games which may take even months to complete the Overseer(DM) may choose to only appear when it meets his schedule or when one of the players sends an email requesting investigation, fixing terrain/structure bugs, map expansion, etc., .

As I mentioned earlier the Overseer(DM) does not have to play every turn within a game.  The Overseer(DM) can walk away setting his position in sleep mode where regular gameplay continues.  No real restrictions... only opportunities for increasing the games replay value.

This would be just perfect for an alternate mode of the game, just like how L4D has Versus.

Just off the top of my head there are two ways you could have fun with this:

1. 7vs1: Every player starts out with a modest civilizations, they are all allied in one unbreakable alliance. Opposing them is "god", one (optional!) player who directs (but does not control) a supremely powerful AI civilization. The object of the game is for the 7 allied players to unite and defeat the AI.

2. Dungeon master: Just like a normal game of multiplayer elemental. The only difference is that a single "ghost" player has complete control over random events and the quest based victory objectives.

well, I mean are you really saying you'd want things to be placed on the map in real time?   L4D has versus, but its hardly giving the player control of the master AI, in fact, quite the opposite, its giving the master AI more control of the player (forcing them to change characters and respawn as tank and so on)

I'm not saying its a bad idea, I'm just saying it doesn't really sound like...   this game.     I mean, if something is going to be added to the map, I want it to be an event or something like that.  I don't think the story/events should be designed for human control, it just seems like the wrong direction for me.   I especially think it would downplay some of what the players have to deal with as being channelers.   By putting the world in the hands of another player, it changes the scale that the channelers would have be working to achieve. I can't speak much for what exactly Stardock wants players to 'feel' when they are put behind the reins of a channeler, but if they want the world of elemental to feel alive and mysterious they can't allow it to be just another player.

I'd be down for giving a player control over all the neutral factions, random mobs, and such as that, but I'd imagine it to be really boring for them since they'd loose half the game. 

GM players create a very different atmosphere from AI or mechanical opposition.   Look at board games like Decent (GM player) vs.  Arkham horror (mechanics opposing).   The way the end goal is viewed by the players is very very different, and not just because you loose arkham horror half the time, its because no matter how tough the enemy is, when it becomes another player it takes away its fangs and leaves it entirely to the players to put them back.   (and lets not even get into superiority complexes created by being allowed to play the GM in such games.  I've stopped playing certain games with too many friends because of this effect)

There was a really good interview with some blizzard devs about why the introduced the burning legion in warcraft 3 for the reason (its where I get the metaphor 'fangs' to represent player respect, since they talked about how they didn't want the burning legion defanged by letting them be playable.), sadly I can't find it among the crap that is most WoW story content and interviews.

(sorry to any WoW fans, just my opinion, take it as nothing more.  I will stand by the fact that WoW has destroyed the eredar and the burning legion's image created by warcraft 3, but talk with me about it elsewhere.  I'm just using the example)

Well, that kinda goes without saying.   I imagine that role is often the 1st thing to be cut from almost any project in which it MIGHT be playable since it takes so much time to properly create.  Its hard to give bad published examples, but I've had enough rapid game prototyping to tell you when you do come accross a bad example, it does leave a bad taste in your mouth.   It isn't even that the GM role is not fun, more over it is just apparent how broken a system really is (especially with the wrong person in the driver seat).  I mean, you really can't cut any corners, which is something you sadly need to do once in a while to actually have a playable product out sometime in the decade that its announced *cough*dukenukumforever*cough*, and pretty much all forms of media have that point where the write/artist/animator says 'its done!' without giong back and adding or fixing something that might make it better.

Really what it comes to be is when it adds reply value, at what cost?   its hard to even say when just looking at it on paper, since its one of those 'looks good on paper' kinds of ideas.  so I'm reserving further judgement on the subject until I get my teeth into a beta to see what the game IS like before I'm going to make any further assumtions about what it is going to be like.

The beauty of a DM controlled story is that the story ends when the DM says it ends. If the players derail the story and make it crash and burn that doesn't count.

If the quest scripting engine is robust enough the DM could drop down various story conditions during a normal game. There could be a big invasion from another continent and a story based quest to repel it. IE kill the general/head honcho guy of the invading civilization. The player who manages to pull it off gets the prestige of a win but also most of the tech used by the invading force. The DM could then slap down another quest for everyone else who didn't beat the first quest. Steal the technological secrets from player 1 before he can fully unlock them.

Since these things play out in game turns and not real-time the DM doesn't have to be around for the whole thing. In fact it might even be possible to script out the whole thing from the beginning and only intercede to keep things on track.

My favorite thing about refs in table-based RPGs is that they have the power to 'break the rules well.'

Having a role like than in an online TBS-RPG fusion could definitely draw me in, provided I found a ref whose style I liked. I'm especially intrigued by the idea of a game that could have a ref who did not need to actively work every turn.

I didn't ref real RPGs as much as I played them and doubt I'd want to ref online these days, but hypothetically, I'd be really interested to see what might happen if I built a world, ran some players actively to get them all comfy and 'started,' and then left them alone with the automation for a while. That almost sounds like it could provide a 'whole new game' on account of the radically different user perspective on the engine. Modding is a clear path to deep replayability for many folks, so maybe a ref role for Elemental could open up a slightly different route to increased bang-for-buck.

Although this has a few legitimate issued from a gaming perspective, it would be SO INCREADIBLY USEFUL from a modding perspective! Of course, this is provided that you can set up a game containing only AI players with yourself as the Overseer, but still... I'd be willing to try it out.