When I read in README.md that annotations are currently stored as JSON, I recalled that there is a standardised JSON notation for RDF graphs called JSON-LD (homepage, full specification).
For now I think it's a priority to use a triple store (#1), so this issue is definitely a low-priority one, but if JSON should ever play a role in future, I'd consider using JSON-LD, as it covers the full RDF data model (so that annotations can become arbitrarily complex).
When I read in README.md that annotations are currently stored as JSON, I recalled that there is a standardised JSON notation for RDF graphs called JSON-LD (homepage, full specification).
For now I think it's a priority to use a triple store (#1), so this issue is definitely a low-priority one, but if JSON should ever play a role in future, I'd consider using JSON-LD, as it covers the full RDF data model (so that annotations can become arbitrarily complex).