We have a request to translate a service request to Spanish (and several others that ought to have translations even if that hasn't been requested), and currently the only way to facilitate that would be to either display English/Spanish side by side on the same SR or set up redundant SRDs in a way that's compatible with our existing approval processes and flows/record change processes/workflow rules (where applicable).
An ideal approach would be to specify on a per-SRD basis what the primary language is and what the supported translations are. Additionally, SRDs shouldn't be allowed to be marked "Online" unless translations are available in all languages for all fields. Users would be shown the appropriate translation based on their language settings, and the primary language would be defaulted to when no translation is available for a user's language.
For any fields with restricted input (picklists, checkboxes, etc.), the stored value should be specified once in the primary language, and the displayed value should be specified in all supported translations. This would be to maintain compatibility with conditionally displayed fields, template invocations, approval process logic, validation rules, etc. Other inputs would simply need labels specified in all supported languages.
We have too many translation candidates to make maintaining multiple SRDs a viable option, so this would be a massive improvement.