Ok, got the conversion working. Basically, for existing shards, it cycles through the xml docs in the Spawner folder, and looks for that spawner in the world via UniqueID. Some spawns that don't have a unique ID, use location/map to convert. It's going to omit spawners that have special characters in it that XmlSpawner uses, ie comma, <>, {} etc. Standard spawners do not support functionality for these special characters.
Now, from a fresh install, do we want to use standard spawners as default? Or XmlSpawners as default?