WARNING: SPOILERS BELOW.
I believe that Hiram Burrows was an agent of extreme order (destroying anything that didn't fit with his plans, extremely afraid of change and of the unknown, etc.); same deal with Havelock for the most part. Corvo is an agent of chaos, which is the main reason Havelock wanted him gone (he couldn't control him; that paranoia led to him killing the rest of the Loyalists). If Corvo spreads too much chaos, however, the balance is once again overturned and the city collapses, in High-Chaos Emily Dies, or in the High Chaos Emily Lives ending, requires another over-the-top agent of order to restore things to 'normal.' If Corvo has low chaos (It's important to note that the game calls this 'low chaos,' and not 'no chaos,') the balance restored from the excess of authoritarian control present before his actions, and Emily is able to take over as a fair and just ruler.
This is even apparent in the differences between the last mission's low-chaos and high-chaos version. Instead of being totally in control like he is in the low-chaos version, having killed his two allies quietly and without much fuss, Havelock is locked away in his light-tower, suicidal and completely and utterly mad (as opposed to just kind of mad).
This is obviously just speculation except for the bits that were fact; anyone have any opinions on this?