User blog comment:B214/Question and Answers 3/@comment-4547267-20140716071719/@comment-73.178.133.185-20140716140043

Issei not being traumatized by Raynare basically means having not been killed by her, and thus him not becoming a Devil. But, let's say that he wasn't traumatized by her in spite of what she did to him. As B214 said, that doesn't change his naivety when it comes to women. At best, he may have confessed his feelings for Rias earlier than he did because without his trauma he would have been able to harbor the hope that her actions towards him were indications of mutual love (which he unreasonably denied because of it). However, even that may not have changed due to the situation of him being her servant, which was one of his biggest excuses as to why she couldn't be in love with him.