Looks like Samsung are addressing the storage issues on the S4 with a software update that will allow apps to be stored on ones SD card.
http://www.theverge.com/2013/6/6/4401652/samsung-galaxy-s4-update-storage-improvements-sd-card-apps
http://www.theverge.com/2013/6/6/4401652/samsung-galaxy-s4-update-storage-improvements-sd-card-apps