To be honest, between the 2 solutions:
- delete all data (100% chance of data loss)
- a fix (X % chance of data loss)
I am pretty sure everyone will try the fix before removing data 
I understand elasticsearch is not a data-base, but only a super indexer/searcher service and its data must be always backed up somewhere. But in some cases, we are using it as primary data source (for log analysis) so we want something really reliable.