With only one episode left of Breaking Bad, it is time to ask one of the most fundamental questions: is Walt a worse principal than he is an agent? That is, he is bad at both, but where does he really fall short: as the one issuing the orders or the one taking them?
In principal-agent theory, both sides can do stuff to screw things up. Sure, it might be in the nature of agents to shirk or be opportunistic if not properly managed, but it is up to the principal to hire the right people, give just the right amount of discretion, engage in sufficient oversight and provide incentives.
Walt has played both roles, as he was most clearly subordinate to Bogdan, the school district, Gus and even perhaps Tuco. On the other hand, he also was a principal, serving as the boss of Jesse at various times as well as Badger and Skinny Pete. And, of course, Todd and his friends/relatives.
So, let's ponder Walt as agent and then as principal. As an agent, Walt constantly tried to evade oversight especially as he sought to do both more and less than his principal, especially Gus, wanted him to do. This behavior ranged from contacting Gus or trying to get another agent, Jesse, to work against Gus. And, of course, the latter meant getting Jesse to kill Gale and then try to kill Gus. Ultimately, Walt kills Gus, which makes him a really insubordinate agent, right? He just couldn't stick to making meth, taking the money, and staying out of trouble. Walt also violated the rules of the first employer we saw in the series--the high school. He used its equipment to make meth and then, well, got creepy with his boss, so he got fired. Anyhow, it is very clear that Walt epitomized the worst case scenario for the agent dangers of opportunism and shirking.
But Mr. White was not that swell at being a principal either. In making his meth empire, he picked Jesse to be his primary agent, which was a mixed outcome given Jesse's addiction (to drugs) and distractions (his ladies). Plus Jesse turned out to be the drug dealer with a heart of gold or something, so he didn't always want to do what Walt ordered. More problematic were subsequent hires: Badger (who tried to sell meth to a cop) and Todd, who exceeded his discretion by shooting a kid. Yes, over-enthusiasm can be a problem. Oh, and Walt decided to hire Nazis to work for him, and they apparently do not take no for an answer. Smooth move. Sure, Walt hired Saul, who turned out to be an extraordinary agent, providing sage advice (even if Walt tended not to listen to Saul), doing what needed to be done, and ultimately sacrificing his own thriving practice. Otherwise, Walt was not so good at agent selection.
Walt also was bad at providing incentives to his agents. Sure, he paid well, but he also constantly berated Jesse, making him feel inadequate. Jesse would have been a fair more responsible and responsive agent had Walt treated him better, but that would have required way more patience and empathy than Walt was capable of. At least Walt did not try to kill his agents unless he really, really had to.
So is Walt as Principal > or < than Walt as Agent? Well, given that Walt as agent killed his boss and destroyed his agent's meth empire, I would have to go with Walt as agent < Walt as principal. But he made it close. Walt as bad human being made him bad in either capacity, of course.
Who was the best agent? Mike, of course. He followed orders and stayed within his boss's intent when granted the discretion to make decisions. Gus didn't have to engage in intrusive oversight over Mike's behavior. No, he had to use Mike to monitor Walt--this was expensive as Mike could have been used to deal with other problems, so the opportunity cost here was pretty significant.
Who was the best principal? Gus, of course. He tried to be careful in hiring, reluctant about hiring Walt given his inherent unreliability, but hired Mike and others who were very good at staying within their lanes. He tried to develop alternative agents (Gale, Jesse) so that he would not have to rely on an unreliable agent. He used Mike as well as technology to oversee Walt--the camera in the lab to name the most obvious one. Gus provided excellent pay as an incentive, but also demonstrated with a box cutter how he would punish bad behavior.
Is this too much over-thinking? Of course, but it could be worse--I didn't even apply chapter two of Dave and Steve's new book to the collective principal in the first part of the last season--the Mike-Jesse-Walt troika.