Rediscovered, in this world. If it helps your imagination, think of your territories as all being completely underdeveloped third world countries whilst the Old Empire is the equivalent of a rather isolationist, decadent first world. The technologies exist but you don't have them and the OE is so isolationist you can't steal or trade for them. What you're really doing is rediscovering technologies that are already in existence.
Steampunk could be rediscovered by 1020, 1030 if you made a solid beeline for it. As pointed out, the calendar is dated from the Spell of Mastery being cast. There is however nothing wrong with sticking to solid physics.
Game balance in combat continues to be an issue; I will probably continue to tweak the base of combat further in this game. The ultimate aim is that elite units should be able to maintain their own against a number of weaker opponents without being wounded or destroyed in most situations. Right now there's a lot of variation that's favouring zerg rush tactics a little too much. Zerg rush tactics should be viable, but five heavy swordsmen should still have rather more than a 70% chance of winning vs eight spearmen militia.
One aspect that may change this is researching armour and weaponry techs; they will add bonuses to light and heavy infantry (though possibly not militia) without changing their upkeep and purchase values.