Hello and thank you for mariadb,
If the --innodb-optimize-keys mysqldump option was available with MariaDB I would use it when backing up and moving tables using mysqldump. It can also be used to shrink InnoDB table files on mysqld instances where "ALTER TABLE table_name ROW_FORMAT=Compact" does not result in fast index creation being used and where expand_fast_index_creation is not available so "OPTIMIZE TABLE table_name" and "ALTER TABLE table_name ENGINE=INNODB" do not use fast index creation.
Having support for expand_fast_index_creation would also be great, but I think there is value from just adding the pragmatic mysqldump option.
Applying the latest changes with fixes for the mysqldump option to MariaDB 10 was relatively easy. The original work and subsequent patches with tests having been created by Alexey Kopytov.
Here are some links to the background:
I tested using the example from Mark Callaghan in http://bugs.mysql.com/bug.php?id=57583