We are using partitions in order to handle unchecked growth of our InnoDB history tables. It's hard to define a cutoff age to drop off partitions though when we have no way to define a globally enforced max value for the history retention on items. I would ideally like this to be something that can be implemented on trends as well.

Enforcement of rules such as this are going to be important for us going forward as we roll out access to Zabbix to additional users. That being said, another interesting approach to this would to add an attribute to users or user groups in which you define these maximum values.