User blog comment:DarkLordZeta/Is it just me or has Fairy Tail/@comment-74.61.227.152-20140410223732/@comment-7418318-20140411074305

Welcome to the Wikia.

Jellal's amnesia was not a way to turn him good, since he was good from the start but turned temporarily evil by Ultear's manipultions. The amnesia was a way to leave both the readers and Jellal himself in suspense whether he was really back to his old good self, or whether the brainwashing permanently changed his personality to the worse.

It also worked as a shield to protect him from Nirvana's pre-release effects, since with all his guilt he would have been susceptible to the same thing that happened to Hoteye and Shelia for sure.

And I think having two different "roads to redemption" for Ultear and Jellal was better than repeating the same way twice.