Binlog rotation based on slave state.
if one of the slaves is down, do not purge binlog files.
if all slaves are health, purge binlog to keep the number of binlog files to a absolute minimum.

Usualy mysql replicates with binlog files.
But they get cleaned up based on a log rotation script, not based on the fact is there still nessesary or not.
I build a PHP script that connects to alles slaves of the master to check if there in sync or not and my script
cleans up the binlog files as soon as there no longer needed. (http://forums.mysql.com/read.php?52,210712)
I would love to see this functionality build in into my mariaDB servers.

note by Anders Karlsson:
As for your ideas on Log rotation, I can see this as being useful,
and possibly this could be considered for inclusion in MariaDB. I
suggest you report it as a feature request in the MariaDB bugs database:
https://mariadb.com/kb/en/reporting-bugs/