I'd rather just have the fewest number of vassals and be VERY nice to them.  Or make them afraid..very afraid to cross me.

I'd imagine that razing a city has multiple effects, which should be kept distinct.  A lot of the talk is saying that razing a city that should not be taken lightly, which I agree.  But it has a lot of side effects, some of which can be positive, depending on the situation:

1.  The empire that had the city is weakened.

2.  The enemies of that empire are happy that it is weaker.

3.  The allies of that empire are mad that you hurt their ally.

4.  You hurt your future of taking that city and devleoping it into one of your own.  If its not a city you could reasonably hold, then this is not of consequence.

5.  That empire is going to hate you.  This isn't just a land dispute anymore - this is outright war.  

6.  Peace-keeping nations are going to dislike you, and war-mongering nations aren't going to care.

7.  Nations will fear you!  You're no longer the friendly Roman empire, marching into a city, claiming it as your own and putting up a flag and changing who they write their taxes to.  You're Ivan the Terrible, you're Genghis Khan!  You don't keep prisoners, even if they do.

8.  Royal ties to those killed in any instance will hate you.  Although I suspect that you should be able to attempt to capture royalty, even if you raize the city.

9.  Royalty born in that city will hate you.

10.  The actual people of their ethnic background are going to hate and fear you, unless they are the war-mongering type.  This makes other cities of the same empire's easier to govern at first - "Hey, they burned down Chicago, I'm gonna listen to what he says or they'll burn down Atlanta too" - but harder long term.  "I'm not paying my taxes, it'll just go to those Chicago-killing Canadians!"  Obviously this effect rolls over into cities you already have control of (say, that one elven nation you have on the other side of the map), because you killed their kin.

Maybe add a second kind of raze, one that takes a few turns and is "kinder" maybe called forced relocations, it would destroy the city, but give minimal fallout aginst you, as you let the citizen take some of theyr stuff whit them then leave for where they want, it could also provide some resources from the looted city, chance at capturing rich noble, one of a royal line, get information or other stuff. and Razing the city would just slash and burn it, chase the citizen away in what they are wearing/killing the citizen, leaving no resources.

No, time wise it shouldn't take more turns, just lower the armies movement on the turn after.

One of the biggest negatives of "colonies" and vassals in Civ4 is the "team diplomacy" factor.  If you are friendly with anyone you are generally safe from being attacked by them.  But, if you immediately form or take a vassal the AI considers the "average" of their diplomatic rating for you AND your vassal - which basically makes playing friendly with big neighbors impossible unless you go solo.  Avoiding this downside should be considered if you want to make vassals feasible in both peaceful and war-mongering empires.  Especially "colonies" but even normal vassals shouldn't utterly destroy political relations.

As for the "leader" of the new nation; I would expect that there would be a number of independent tribes that do not have channelers as their leaders but still have a leader (or group of leaders).  I could also see particular independent heros providing protection to these settlements.  Likewise, having heros and other channelers press for the freedom of a group of people would bring an interesting dynamic (e.g., Aragon agrees to help you if you give the people of Rohan their independence).

Lastly, the ability or inability to keep together large nations should be somewhat dependent on how loyal and effective the local ruler is that you assign to the region - and maybe partially dependent on what kinds of magics you control (such as teleportation, crystal balls, etc...) that allow your character to have influence over larger distances.  The familial diplomacy aspects lead toward this kind of consideration as well. As can a form of "Civics" implementation and also military police (though how loyal such an army and command is to you would be a consideration).

In this world of magic however, it seems news would travel faster. Since I have also heard that many of the battles will take place in regions (i.e. all part of a larger picture), that would mean these towns and cities would be fairly close together (so it would offend more people, faster). Most civilized nations did not raze cities, unless they were so inferior as to be not worth the updating. I know in Rome Total War, there were tons of cities I hated to take, it taxed my economy so much to hold them and keep an army nearby. But once I held that city long enough it would become a powerful addition to my empire.

Razing a city because you can't hold it does make sense, but really, you should only try to invade when you think you can win. Taking a city you can't hold is overstretching your empire, which is something you would only do in a short sighted situation. It would seem more useful in this situation to liberate a town, making it a vassal (preferably a puppet state), and causing negitive diplomatic actions toward any empire that tries to take that town over.

@Kellendrunk: I save that power for when it's needed, maybe when we're playing, I'll kindly ask that you and your armies politely kill themselves.

Lol, I didn't even know that. That is definately not the way to handle vassals. They should know that too, Mr. Spock even says so when you discover vassalage:

"I will to my lord be true and faithful, and love all that he loves, and shun all that he shuns."

That means you don't deal independently with vassals. If a vassal is causing your friend greif, it's treason.

I think you guys are forgeting that cities take up more than one tile in this game...You won't (or atleast shouldn't) be able to just waltz in and raiz a whole city to the ground in one turn as you can in Civ4. Also, 20-25 is pretty gigantic if those cities are well developed and take up many tiles. Also, while 32 is the max number of factions you can play with, the game only have 8 cannon factions, so when he says that 20-25 is large number of cities, I'm going to assume he means in a game with the 8 cannon factions.

It all depends on the time base of a turn Stowe, it doesn't take 6 months, or 3 months, or a month, or a week to raze a city.  It takes a few hours.  Fire is crazy like that.

EDIT - With, of course, more time being taken if you get the citizens out...althoguh usualy if you're gonna raze a city your troops have already messed up the citizen population pretty badly..

Minor correction: there are twelve canon factions, 6 human and 6 Fallen.

On razing cities, the Great Fire of London took about three days and didn't completely destroy the city. The ancient Romans took roughly a fortnight for just the burning part of their razing of Carthage; they also destroyed the city walls and the harbor. Stone walls and buildings don't burn, but if you're really pissed at an enemy, you can take the time to tear them down with siege engines.

Hopefully, the multi-tile city structure will enable a thoroughly satisfying, somewhat time-consuming way to raze city.

Well, have you seen the videos from PAX? 1 volcano destroyed a city.

What will come after Elemental? Maybe a RPG game where you can enter your Elemental's game, and try to deal with the current faction present?

And don't forget to add in additional time to sow their fields with salt if you're really ticked off at them.

Besides razing towns, there is the other historical method of subjugation. It's called slavery.

All you have to do is round up all able bodied persons, and take them in chains back to your towns to work your as slaves.

Has there been any word on slavery? Cause for the mordor-creating-evil-channelers it most certainly feels appropriate.