At least when he explained it. Nightwing was used to homage two of the early influences in his life: Batman and Superman. Nightwing was Superman's identity in Krypton when he had to take on a "Batman-style" role, so it makes sense for Dick to adopt something like that.

So what would make Robin adopt a new mantle? He'd have a little bit of Batman, but also Dick Grayson in his name. I still like the name Redwing or Batwing. Redbat just sounds weird.

- l.k.