We should support enforce_storage_engine, like Percona Server 5.5/5.6 has. Description: http://www.percona.com/doc/percona-server/5.6/management/enforce_engine.html
Use case: To improve management – eg. enforce_storage_engine=InnoDB – this ensures that people don't create MyISAM tables by accident.
Customer requests: There have been no customer requests for this yet from MariaDB Corporation.
1. It is however likely used in HPCloud, DBaaS – see: https://github.com/saurabhsurana/trove-installer/blob/f7cf7824fb7536b16da073ba7fdb0e717da26fb1/saltstack/states/trove/taskmanager/mysql.config.template
2. We have had a migration from MariaDB 10 to Percona Server 5.6 at a bank in Germany performed by FromDual for this very reason – http://www.fromdual.ch/de/node/1074