Using the Batmobile template project, exporting using textual syntax and importing back the exported sysml file does not import all the elements.
It succeeds with warnings:
Following messages have been reported during conversion:
[Warning] Unable to resolve name 'System' for reference 'superclassifier' on element '[Subclassification] Batmobile::Batmobile::<Subclassification>'
[Warning] Unable to resolve name 'problemStatement' for reference 'redefinedFeature' on element '[Redefinition] Batmobile::Batmobile::<FeatureMembership>::<ReferenceUsage>::<Redefinition>'
And the imported model is far from complete:

Using the Batmobile template project, exporting using textual syntax and importing back the exported sysml file does not import all the elements.
It succeeds with warnings:
And the imported model is far from complete: