I know this is an old question, but I just wanted to post a +1 for requesting this feature, there is currently an export_preset AppleScript function, but not an equivalent import_preset — it would be nice to have the symmetry there.
However I also found this: Syncing the config in Git - #4 by Andreas_Hegenberg
Perhaps autoloading would work for some use cases that automated import would be used for? I can't find any documentation elsewhere about this feature but I'm going to try it and see if it works for my use case.