^ Well Neeson was basically repeating his supporting roles in Kingdom of Heaven and Gangs of New York, only in Batman Begins he got to return for the third act.
And, to some extent, his role in Phantom Menace. He's basically turned into Sean Connery over the last decade, playing all those mentor roles Connery did in the 1980s and 1990s. I think in BB, the idea in his casting was to subvert his association with that sort of role. Which would explain why they were also after Mortensen, after he played Aragorn (any relation?).