A definite yes to Robin... and throw in Nightwing and Batgirl/Oracle while you're at it. At this stage I'd luuuv to have a Batman solo be all about the Batfamily. Not just as cameos/fanservice, but as the actual backbone of the film. A structure of flashbacks to all the biggest hits - Dick's training, his falling out with Bruce, the death of Jason Todd, the shooting of Barbara - interspersed with the main storyline, something that forces them all back together. Add Tim Drake to the mix, if he fits. Explore Batman's "mandatory" loneliness as something that ought to be questioned, and the idea of allowing kids to become vigilantes to channel their pain towards something useful and inadvertently building a legit family out of it, Alfred included. That alone seems like such a juicy thing to build a Batman movie around. Not to mention that it'd be a piece of cake to market.