Definitely could have done a side hill patio on that side as well as the other but if you do too much to avoid the earth berming, at some point you just have a regular house
Finding the perfect hill can be difficult too when you have to take into account solar gain and staying on at least and approximate east/west axis.
Packing tires is horrible though to be honest, I've looked back many times and wondered if I could have gotten away with earthbags. Let me know if you find the answer to that question, or maybe I don't want to know haha. My feeling is that it would have to be a perfectly round structure to give earthbags enough strength which creates its own challenges in an Oehler concept.