Awfully weak story... or is it? [WARNING:SPOILERS]

[Ramzal]

-snip-

You do know how conquest of an area goes, right? The area is taken over, the culture and lifestyle of the people is all but annihilated and there is a large increase in crime, murder, etc. People are resistant to change, especially on a macro scale. Eorzeans seem to treasure their religious rights to worship the Tweleve, and that would be the first thing to go namely because the Empire sees them as false gods. This would just lead to internal rebellion if the Empire -did- win and more bloodshed on a pretense that they're "Just trying to help" when in reality they're looking to expand their lands and become more powerful. The only reason to give the other side a chance to surrender is so that YOU don't use up resources that could be used anything else.

He was using Ultima Weapon as a "balance" to soften the blow of being taken over. "Sure I'll come to your lands, tell you how to live, what to believe in, and pretty much wreck your entire concept of life but... I'll get rid of these monsters for you." Which if you look at it, Ultima Weapon was a pretty poor bargain. A group that was given a blessing of some sort trashed that machine and look at what happened--the primals got out of it. Gaius didn't eliminate the primal threat---he contained it. Very poorly and with technology he didn't even fully understand and was tricked into using it. Why in the heck would you follow someone who just finds something, doesn't fully research it extensively enough and just uses it right out the flood gate without any second thought?