The one thing that might really bother me at RoP is if Gandalf is meteor man (or if they try to shoehorn him some other way). As I mentioned before, Gandalf did not a arrive until well into the TA. If they try to shoehorn him in, it means he will be at least aware of the major events at the end of the SA and he won't have to do research to determine that Bilbo possessed the One Ring. As it stands, Gandalf's lack of suspicion here is already somewhat dicey even in canon - surely he would have time to do a little light reading given he was on ME for thousands of years before Sauron's final defeat. He knew about Gollum and that the ring had extended his life far beyond what was normal (and suspected the same of Bilbo)