[Endoperez]

Magic can be researched, and it does change the world. However, even if a mage can enchance the walls of a city, the masons of the city can't build a new castle whose walls are as good as the magically enchanced ones.

A historical empire dropped into Dominions world would come up with uses for magic, of course. All the nations in Dominions already have come up with all kinds of uses for magic. Many have uses for Faith too, for that matter (Arcos scrying dominion, MA C'tis Miasma dominion, etc, and then all the spells that work better in your own dominion). However, this has taken much longer than 50 years. Why do you think technology would be any easier to develop?

Magic and technology can and have been interwoven in Dominions. Ulm uses Black Steel armors! EA Arcoscephale has build flying contraptions! LA Man mages have siege bonus and can spy, doubtless with the help of simple Earth and Air magic! EA Vanheim and Helheim commanders use magical armors! EA Atlantis has Basalt Spears and Armors! And then there's Caelum who uses magical weapons and armor throughout all ages... But all of these combinations are heavily guarded secrets. The ways of mass-forging Black Steel were forgotten between middle and late ages. After Early age, the only flying armor is the super-heavy Stymphalian suit of bronze wings. LA Atlantis had to steal the secret of ice equipment from Caelum. The changes you suggest are too drastic for anything but time to solve.