Dragoons provide a bonus to keeping civil unrest down? If I remember correctly, the narrative mentions this but I didn't know it would be reflected in-game. By far the worst for me was Vienna. I had to keep a full stack there for ~18 turns and a half stack for another 10 to put down the continuous rebellions. When I captured it the plebs were at -30something happiness. I have never seen the occupation figure shrink by more than one per turn, regardless of how many troops I keep there. You would think a brutal peacekeeping force led by a decorated general would have a long term impact by influencing the rate in addition to the per-turn garrison.