He's always been an insecure man, sure. But the entire "Jack the Ripper" persona BS just came out of nowhere, in MGS4 he never once went total psycho despite being pushed to the limit...and in MGS2 he was a rookie spy so no psycho there
But at the end of MGS4 he had a family , in MGR that is barely mentioned in game. The ENTIRE point of Raiden in MGS4 was to come to terms with his past and regain his lost humanity, and he finally does exactly thar, when he's accepted by his son...and in MGR he pretty much claims that he's now a killing machine....¬¬
Platinum pretty much SUCK at stories, and they turned Raiden...a cool tragic character into yet another white-haired anime hunk with a big sword and some evil alter ego....
I do not HATE MGR....but I expected better
The original "Between MGS2 and MGS4 plot where Raiden has to come to terms with his new body" idea was waaaaaaaaaaaaaaaaaaaaay better, but shoehorning it after Snake's dead and the finale of his saga...just no
Actually Platinum Games didn't write MGR it was Etsu....something something and other workers from Kojima Productions.
Kojima only hired PG for gameplay.
The story, art, and enemy/character designs were done by Kojima Productions although PG had their fair share of creative inputs (they were the ones who suggested a sequel to MGS4 rather than a prequel, the original plan, for more creative freedom as well as came up for the idea of Sam and his design).
In defense of Etsu writing and Raiden's character events from Raiden's past were brought up in MGR such as being used as a child soldier and his past life as "Jack the Ripper". Raiden before the events of MGS2 took severe counseling to get over his past after the Liberian war and was able to adapt in society as Jack/Raiden. Nothing happened in MGS2 or MGS4 that had Raiden recall of his traumatic past.
Those innocent kids being used as child soldiers and having their eyes and brains being harvested to be used in cyborg soldiers, the same cyborg soldiers that Raiden has been cutting down for sometime now. So not only could he relate to those kids since he was in their position but the poor kids were being forced and used for evil purposes by an organization he bears a grudge against and were sent to their deaths to his (Raiden) very hands. Coupled with his dying anger towards Desperado that was still growing and more memories of his former life coming back to him, a life and memories he wanted to forget, and lets not forget being pushed to his limit and the stress of it all created a mental pressure far greater than anything Raiden ever experienced in MGS2 or MGS4 making him recall his former life as a child soldier and adopt the persona "Jack the Ripper" he once abandoned and wanted to forget.
My only gripe with Raiden's character arc was that after he defeated Armstrong and Desperado he didn't return home to his family or at least think of his family and how they will feel about him going back into action.