Are there different research trees depending on race or choices made? It would be interesting to go down initially slightly different paths that end up in very different results.
For example, you could go down a route that exploits and focuses on the rediscovery of magic that starts off with augmenting resources and troops and ends up with producing new resources and troops with magic. Said magically made troops/monsters/demons would be expensive and slow to produce but very powerful along with producing groups of weak troops cheaply and quickly. You could make use of magical defences. Plus this could be split into a kind of 'elven' group of nice happy magic, and 'demonic' group of evil magic, which would be different but both technologically challenged.
On the other hand, you could have a balanced approach of mixing magic with conventional improvement methods and rudimentary technology. Rediscovering armour and doing farming the hard way could make your citizens and soldiers generally hardier and tougher (ignoring magical boons), as they are not used to the convenience of magic for everything. Forged armour could be cheaper yet generally tougher than all but the most powerful of augment spells, and warriors would generally be more skilled in hand to hand combat, but economically you could be less capable of production or resource extraction.
Another group could rediscover magic but then focus on making use of it in technology, steam-punk style in a way similar to Final Fantasy VI. It would start with odd technological bonuses like using a crossbow over normal bows and more efficient water wheels or whatever, but end up with magically animated machines which are fragile but incredibly powerful and a hugely advanced level of production, giving the most powerful late game at the trade off of a weak early game. Plus this could be unique in the sense that with this tree you stop rediscovering and start inventing.
Plus this kind of thing fits in with the 'whole evil beings fight good men -> mens ingenuity allows then to beat evil things -> ingenuity eventually makes men worse than evil beings in first place' that everyone loves.
