No son please ! ^^
You don't need to delete your movie partition to get more games on your HDD. Just delete the movies to free the space.
Usb loaders can now read Fat32 and NTFS partitions too. So put your iso games into the movie partition.
You only have to switch between the partitions on the usb loaders before loading the chosen game.
Usb Loader GX and Configurable usb Loader have this switch function into their last reviews.
You may have to recompress your Iso's in other file format like .wbfs (or split them if they are larger than 4 Gb in Fat32)