Make merchant lord a level 4 or 6 perk, optionally, and add in a feature where you no longer gain any XP from questing or exploring.
This is a very powerful perk, I would even say the most useful rogue perk. I would agree that the 'no questing' option would balance it out, but there's a reason to have quests and explorable exp and that's to be able to do them with ally PCs, without any reason to quest or adventure your PC would just basically be a gold farm who only interacts with other PCs to throw money at them.
I think the perk is right where it belongs, or if anything should be nerfed, application only, or removed. That being said, it's a super fun perk if you survive long enough to earn it.
Not going to happen.