Structured authoring that fits the content model
For a DITA team, a replacement needs to handle the topics, maps, references, metadata and specializations actually used in its content. DITA is an XML-based architecture; support should be assessed at the level of real authoring and processing behaviour, rather than merely the ability to upload XML files.
The OASIS DITA overview defines the architecture and its document types and mechanisms. Use the standard as a reference, then confirm which versions and features your proposed configuration supports.
Ask an author to create and revise a representative topic, use a map, resolve a validation error and preview the output. Include a content architect in the assessment of constraints and templates. Training is a real implementation requirement, so test usability rather than expecting a complex content model to require none.
