Is there a way to have AA produce the two-character country code in the geosegmentation instead of the full country name? Is this something I could rig up with a custom dimension?
I don't find classification's for countries to check country codes as it is not custom eVar, and it is automatically populated by the system, so if you have more questions then you can reach out to analytics customer care.
But, you can handle this using custom eVar, but getting visitor country code involves complexity and you need to handle this at your application level
if your application uses Akamai CDN then your application developers can get country code and pass it to the analytics variable, or your developers need to use some ip location database to get to country codes.