In many strategy games, wars are either of obliteration or subjugation. I'm wondering if, in Elemental, this might be handled differently. Rather than obliteration or subjugation being the easiest route in war, perhaps raiding and slaving would be the most cost effective, short term strategy.
This could be done fairly easily. In most strategy games, when you conquer a city you are given a spur of the moment decision. If you decide to occupy a city, your soldiers immediately move in and start oppressing. If you decide to raise the city then--- poof--- the city disappears in a plume of smoke. I'm wondering if, instead though, the only benefit you can get immediately from successfully invading a rival city would be when you only intend to raid and enslave. Once the city defenses are down, the city's denizens flee the sight and you grab whatever valuables you can find, nab some women and children for slaves (your civilization ethics permitting), light a few fires, and head for the hills. After the fires die down, the majority of the city's denizens return and rebuild.
If you want to raise the city, on the other hand, you have to stick around for awhile based on the manpower you have available, burn every last building, salt the fields, collapse the mines, hunt the citizens down in the country side, and beat the foundation of the city into dust. Naturally, this takes a lot of time and effort. If you decide the raze the city, you might even get fewer slaves and gold than if you had simply raided it (in the chaos of razing a city, piles of undivided loot tend to "disappear" and slaves escape.)
Subjugating a city would be even trickier. So the net effect of what I'd like to see is that pettier wealth related wars, rather than empire building wars, would be much more common. Also, relationships with a given civilization wouldnt' decline simply from declaring war, but what you do during that war. If you raid one city and go home, your relationship doesn't take too heavy of a hit. Raid that same city 5 times in 50 years, though, and you can expect that nation to revile you.
Some kingdoms might even gain great wealth, power, and prestige without ever even subjugating an enemy city. Granted, raid an excessive number of smaller kingdoms and you can expect they'll be fielding a grand alliance against you.