Yikes... spliting up their territory! I almost think the Cardassians have been victimized in DS9. I mean... they only allied with the Dominion after feeling helpless (thank you Eddington, thank you Martok, thank you Gowron). And to make matters worse, the Dominion tries to exterminate them! Why are the Cardassians hated so much? All this crap made me kind of root for them at the beginning of the Dominion war..
I think the problem is their government, and what it's warped (most) of their society into. That's what makes them so hated and feared. While we occasionally caught glimpses of another side of them (Daro, Natima Lang, Tekeny Ghemor, etc.), before the rebellion, there wasn't much representation of anything else to them but cold, arrogant, ruthless, "honorless" SOBs.
One of the first cracks in that facade, as far as the entire society is concerned, was the Klingon attack right when they were starting to pull things together into a form that might be a little better than before. That's when I first started getting really annoyed with the way they were being treated. They reform and get invaded for it. Talk about "no good deed going unpunished"...