I do think that there is a massive overhaul needed for hideouts.
I think, with the stealth part, you would be able to avoid confrontation altogether and steal some supplies from them and even rescue prisoners. As you say, fewer people = more stealth. So maybe you could drop off a couple of guys in a camp to steal from it over time.
But I think there needs to be a "powerful military" aspect to it as well. I have seen too many of those hideouts with close to 40 people camping in it.
So it would be nice to assault the camp and surround it using an organized army (the one with multiple lords) to get of them.
And maybe if you have a small party there looting secretly, they would be killed because they would be thought of as bandits unless you're the raiding army.
As for rogue scaling, I don't know much about that. I only have like 12 in my skill, and I only know of 2 ways to improve it. Ransom people, and get caught and escape.