Over the course of the series, Vegeta slowly begins to soften. He learns that standing alone is not necessarily the best course of action, and that he doesn't need to be fighting all the time. It's okay (good, even!) to have someone to watch your back. He even learns to love and has a family that he cares for deeply. This development is likely bolstered by the defeat of Frieza, and I'm unsure how much Vegeta can progress without Frieza being addressed. Vegeta goes as far to say that Frieza made him who he is. It is heavily implied that he does not want to be the person he's become - he's in tears when he confesses that to Goku. Ideally, I would like one of Vatheon's ultimate Care Bears to start Vegeta along the path of forgiving himself. If he could learn camaraderie (as opposed to just, you know, blowing failures like Nappa up), I think that would go a long way, too.