Just a small story-related observation:
The Tech faction, as it stands, does not seem the equivalent of the Magic faction story-wise. Surely, not everyone in the world can use magic; that marks the Magic faction as a specialized group of people distinct from the common peasantry. If technology were taken as the equivalent of magic, then there must exist wondrous devices created by the power of science which can match magic in its specialization and inaccessibility. In the case of the Battle Machine or the Ornithopter, this is undoubtedly true; not everyone can build or operate such things, and, from the viewpoint of our world's own medieval period, these devices seem as improbable as fireballs.
This, however, does not extend to the lower echelons of the Tech techtree. Anyone can use a sword; moreover, the usage of a sword does not imply the involvement of technology, unlike the usage of fireballs, which does imply the involvement of magic. On the contrary, our common fantasy stereotypes have the usage of a sword imply a lack of intelligence, and thus the ability to comprehend science--i.e. "all muscle and no brain". There is also a progression on the Magic side-- Initiate> Battlemage> Archmage-- which is absent on the Tech side. Initiates are capable of small amounts of magic, and they become more powerful as they move up the ranks, eventually becoming specialized magic-users. The Tech workers, on the other hand, receive no scientific education, and thus the Technicians have no precedent.
In short, some Tech units' usage of swords and bows, rather than indicating the presence of technology as Magic's fireballs and summonings do magic, indicates in fact the presence of neither magic nor technology. This renders the Tech faction, instead of the faction of Technology, the faction of Everything-But-Magic. With this in mind, I'd like to propose a few changes, such as changing the Worker unit to an Apprentice unit, or replacing the swords and bows of Tech infantry with more mechanized devices, such as self-loading crossbows or miniature catapults. No gameplay mechanic needs to be changed; all that needs to change is a few names and perhaps graphics, if only to make the Tech faction more congruous to the story.
I am, of course, aware that many have proposed a new Science faction. This would be a prime opportunity to split the Tech faction as it exists in half, and all the hi-tech weaponry, such as the Battle Machine and the Airship, can be relegated to the new faction. I propose to term the remaining elements, keeping in mind our own medieval era, the Knights: those unwilling to abandon tradition to the pursuit of progress, represented by magic and technology. They lord over the uneducated, hard-working masses, who cannot enjoy living in an ivory tower isolated from the hardship of the world and having unimaginable powers promised by magic and science under their control. The faction of the ordinary. Of course, they would have to be given new and stronger units to compensate.
