Ath'kethin
Elder Thing
I always wanted to play DragonStar, and even bought (one of?) the core book(s?) back in the day. I used bits of it in an Eberron game a few years later bit that was that.I started to realize this about dragons a while back, even before I realized this about "evil humanoids". Dragons, in D&D, are usually portrayed as highly intelligent, sentient beings. And not only is a large part of the game's mythos to track these beings down, murder them, take their stuff . . . . but to make clothing and tools out of their corpses!
I made this a plot point in a DragonStar game I was working on, but never actually got to run. DragonStar is an old FFG d20 campaign marrying D&D and Star Wars, essentially. In the DragonStar setting, the galaxy-spanning empire is run by dragons, currently the emperor is a despotic red dragon. I decided that a large part of the reason why dragons banded together and took over the galaxy, is that they were tired of being hunted and made into grisly trophies by the "good" races . . . .
I like your logic for the dragon empire!