Yeah, I wouldn't have minded Steph going back to being Robin if Dick had asked her nicely. I can actually see those two getting along and having a decent brother-sister kind of relationship, though they haven't interacted much before to my knowledge. And out of all the slightly older bat-folk, Dick is probably the only one (save Alfred) who wouldn't have some screwed up reason to treat her badly in the end.
(Batman, because he used her when Tim quit being Robin and the whole "she's just like Jason" BS, Babs because she probably saw too much of herself in Steph and didn't want to encourage her to be a vigilante lest she end up dead, and Tim because what with him being her ever-angsty ex-boyfriend it's probably not healthy at this point.)
It would have been an interesting and refreshing dynamic to have Dick as Batman, Steph as Robin and Cass as Batgirl.