In light of the recent change in vote ordering, a certain aspect of the design process for SO has been highlighted. It seems that certain features, while present in the system, are considered by the developers to be accidental (see this comment thread). In this instance, the secondary ordering of answers by last change was "completely accidental, and was never by design."
Therefore, it seems the developers feel justified in making changes more arbitrarily than they would with parts of the system that were explicitly purposeful and by design. Since it was never intentional and certainly wasn't intended to be permanent, why not change it once a good idea comes along?
While I have no problem personally with the developers using whatever system they see fit to prioritize and implement code changes, I can see how it is frustrating for users (particularly those who frequent meta) to have their opinions weighed against the (unknown) original intentions of the developers.
Should the developers be more up front about which features may change at any time with little discussion, and which are carefully considered elements that will require extended consideration? Is that even possible?
Or is this something that just has to be accepted as part of the package when dealing with a system as complex as SO? After all, not every piece of code and layout is going to have been carefully considered. Therefore, shouldn't we expect that some features are subject to change at the sole discretion of the developers?
At the end of the day, all features are at the discretion of the developers. This is not open source, they own the code base. But I think many people here on meta would like clarification on their role in making these decisions.