One thing that Eragon didn't consider was that his presence would be a danger to the next person on the throne. If he could bolster a rebellion against Galby, then he could do the same against Nasuada. I wouldn't be surprised if Nasuada eventually used the Name of Names to bump off Eragon quietly.

Plus he seems to think that moving a couple of blocks away means he won't ever be tempted to interfere in Alaglag's affairs again now that he's "too powerful". Um, he's still in constant contact with Nausea, Arya and probably Roran as well. The moment he hears anything he doesn't like, what exactly is going to stop him coming straight back and fucking everyone over for a second time?