I've been starting to think about what makes a movement a good movement aside from the obvious: how it confers accuracy and durability to the watch. I'm guessing that for the best movements, each piece serves a specific role for the movement, if not, more than one function. Also the movement has to be designed so that it is easily serviced by a watchmaker, in which the order of parts are inserted in regards to the different Z-axis planes (superficial to the watch case, deeper in the case, to superficial to the watch dial).
I'm interested in what makes a movement horologically significant (aside from the historical implications, i.e. being the very first to employ the design or concept). Why are some movements harder to emulate, aside from patent laws? What's common between all mechanical watches, i.e- mainspring, etc? What requires the personal touch as opposed to machining via Auto-CAD softwares?
Then, I've questions about the casing of watches. It seems we've been limited to precious metals, steel, and more lately ceramic materials. Will the cases continue to be made of these materials or are the watchmakers doing any additional research into new materials?