The point isn't to have realms with few nobles.
The point is not to spread out to as many regions as you possibly can, no matter how few nobles you have.
"Small" in region count, not noble count, in other words.
If you can get lots of nobles, go for it. That's encouraged. And if you have enough that you can take more land and still keep your density up, that, too, is encouraged. Just don't keep taking regions till you have more than one for everyone.
