Hello, I like the Online ID you currently have, but if you were to change it, then I recommend having it with an underscore to split the words and capitalizing the "S" in Shinobi. But in my opinion, it would be a mistake to go with the new Online ID, the other seems much better.
Trophies would be the only reason why I wouldn't change my PSN username. I did change my username way before trophies were implaneted, so I was one of the lucky ones. Just make your username something you like. I love my Username and don't ever plan on disliking it. I put my favorite video game character in it, Sora.