There are a whole bunch of problems with the tech tree that prevents the player from really making a long-term choice for strategy.
First off, Civilization doesn't offer any military advantages other than group upgrades. It is supposed to support a faction specializing in civilization with influence and being able to recruit monsters from the world around you. But these are just woefully underpowered to any trained units.
Second, there is no real choice between crystal and metal equipment. Metal can be used in the warfare tree on its own, and that's a "strategy". But Crystals cannot be used in the magic tree to the same effect. There is no armor, and upgrades in crystal-requirement gear requires that I invest heavily the warfare tree.
The result is that the player is left with many short-term choices (do I get that burning axe now, or get a mounted unit instead?). But long-term there is no real choice in what you go for, which makes it impossible to have a variety in the game.
Each game plays the same: Civilization first until Mining, Trading, Cooperation. Then go warfare or magic depending on if you have metal/crystal. Then go warfare because you'll need better armor for your units and heroes. And then the game is over once you get to chainmail and build a few super-units.
Suggestions: Improve influence-based world resources for recruiting monsters. Preferably by making the existing ones ugpradeable, and making the player pay each time he recruits one, and putting MANY MORE of those world resources in the game so that Influence becomes a viable resource alternative. A wild run-on sentence appeared.
Also create more mid-tree equipment choices for using crystal. That is, enchanted armor for everyone. I don't care if it's twice as expensive as chainmail - give us something. And then disconnect the late-magic tree from warfare tree. A few unit design traits originating from the magic tree would be cool as well.