I can handle introducing horse riding. I intended for that spot on the map called the Golden Barrens to be populated by people descended from Primus' happy following, only they found their way to those steppes and eventually became nomads instead of farmers along the Mahd River Valley. So they'll eventually develop horse riding and such on their own and then be those silly Mongols that always forget that this is Divinus and that trying to sack cities in the nearby ogre empire is ill advised.

Maybe they'll just stick to raiding their distant cousins over in Vetros.

Edit: Also, the ogres already have cave-painting to store knowledge in the form of pictures. Don't make the ogre hieroglyphs be the only form of writing; otherwise Lazarus will have to live with the fact that the only scholars that worship him are a bunch of bloodthristy ogres that just want to figure out how to make new weapons so that they can enslave more people.