How can I edit the Subject of a CiviCase?
It seems from this forum post that the ability to edit the subject of a CiviCase has not been implemented, and that its implementation should be done by creating a new core/case Activity Type for 'Change Case Subject' so that any change was also tracked on the Case.

That sounds a reasonable improvement, in the meantime it seems the only option is to edit the field in the civicase table - which my brief testing suggests doesn't not bring the wrath of code down upon my head