1. Option to store centralized chat history on the server instead of on each client. If a client logs in from a different device or client software, they could still see their chat history from every other device/software (just like google chat). This would of course require client-side support as well.
2. Option to set limits on archive age and/or size. For example, automatically prune any chat history older than 1 year, or prune any user with a chat history larger than 1 GB, whichever comes first.
3. Option to store message archive as a separate (but linked) database. Not sure how complex this is, but I might want to have my normal user/login/group database local on my openfire machine, whereas I might want to offload the more bulky message archive database to a separate NAS.