thats where there's a difference. At least the first 2batman movies had Michael Keaton, Gough and Hingle there were no other characters that required an actor to play a recurring role. After that it was "a new take" on the series. Never a "real sequel" such as Begins and DK. As such with this possible 3rd film, like Spiderman. They were all sequel's in a string 1right after another.
Now James Bond is a completely different aspect which shouldn't even be brought up in this discussion. Why? Because James Bond is a code name for a SPY who can be played by anyone. It doesn't have to be the same actor, unlike with this current Batman. Again with Superman, at least they had the same actors.....actually they kept the same actors for the 3biggest roles, Reeves, Kidder and Hackman.
As for Returns.....once again its a new take. If there's a sequel and characters are brought back (Routh is a given) then the same actors should be as well.
Anywho my point is when theres a recurring role, a new actor completely detracts from the movie.