Very nice...love it.
A few balance (IMO) issues I have seen so far:
rangers are too deadly. 3 of my neighbors were wiped out by one civ in about 20 turns
, turned out there were more than a dozen rangers running around....w/combat 5 each.... Since it is recon, maybe -50% city attack penalty?
some summons like skeleton seem too expensive for their stats. (Compared with, say, Chaos maunder)
Cities overall seem fairly easy to capture. More defense from buildings? More city-defending special effects/promotions?
Drill promotion line seems way underpowered. All the cool promotions are behind the combat line, and a 20% strength boost is not comparable to a first strike chance or two. Combat promotion line tends to be favored even back in vanilla when it gave only 10% strength bonus, and are generally better in FF, where drill is much more powerful than it is here. Suggestion: boost the drill promotions (maybe make drill I what drill II does right now and so forth, and make drill IV, say, 2 first strikes.), as well as weaken the combat line. (15% strength is great enough, given it has additional perks, and it leads to all the best promotions.)
Lastly, pleeeeease take the time and do the boring part of modding--the pedia. It is a pain to find out exactly what some of the features do, 1 line description will do the trick!! (E.G. for witchhut: provides additional spell research; cannot build improvements adjacent to it.)
Now, back to the game!