Grayson makes the most sense, he is just as incorruptible and trustworthy as Bruce but more positive and probably less likely to go down any dark paths that could lead to improper use of the ring. Then again, that lack of negativity may make him unwilling or uninterested in having the ring at all. I really can't wait for them to explore Clark and Dick's relationship in the new 52, which was so strong and such a big part of Nightwing's character before.
Jackman makes a good Wolvie theres no denying that and he is by far Fox's most recognizable Marvel character, so on that grounds alone it makes sense that they would try to get him into as many movies as possible. This is sounding better and better. If they actually stick close to the real story, this is gonna be a good movie.