Well, Hoffman just won and has no chance. Pitt and Mortensen's film weren't seen enough.
While I know that the Academy has often give career awards as "make-up Oscars", but let's look at a recent history:
Al Pacino wins Best Actor for Scent of a Woman, not even close to his best work, but believe it or not the film was also nommed for Picture, Director, and Screenplay. Next closest competitor, Denzel Washington in Malcolm X, a film that had a mixed reception and didn't get much Academy love (plus, Denzel already had a Supporting Actor Oscar).
Russell Crowe wins for Gladiator: Not even close to his best performance, but film also is nommed for many Oscar (and wins Best Picture). Next closest competitor is more complicated. Javier Bardem was critically lauded, but in a foreign language film--nuff said. Tom Hanks already had TWO Oscars in the bag (even though his work in CastAway was better than either of those winning perfs), and Ed Harris, long appreciated, was in a film that only was recognized for his role and Marcia Gay Harden's. Not hard to see why Crowe wins here.
in 2001, Denzel Washington wins for his minor work in Training Day, over a pretty towering Russell Crowe performance. Why? Because Crowe just won, and they're not going to give him the back to back treatment that Hanks got with Gump. Other competitors are Will Smith in Ali, a not very well-liked film, and an overdue Sean Penn playing retarded in the underperforming I Am Sam. Plus, Denzel plays against type and does a character different from all he has done before, which always impresses.
Now it's Penn's turn. in 2003 his histrionics in Mystic River get him a win over his superior work in 21 Grams, an overexposed Jude Law, a not-quite-important-enough Bill Murray, and the laughable Pirates nom for Depp. Mystic River itself is very respected and gets a shitload of noms, and probably came very close to beating Return of the King (note Eastwood's make-up sweep the next year with Million Dollar Baby).
You would think it's Depp's turn, right? The problem is that Sweeney is not going to get more than a few tech nominations (even Bonham Carter seems a longshot at this point), and the competition is FIERCE this time. It can easily be said that DDL is owed for losing his deserved Gangs of New York Oscar, and his first Oscar win was almost 20 years ago. Plus, DDL's film is likely to get some major Oscar attention (though a BP nom is hard to guarantee). It also hurts Depp that this character isn't very unique for him. It's not a far cry from Edward Scissorhands and Ichabod Crane, and the singing isn't a successful revelation on the level of Nicole Kidman singing in Moulin Rouge, or Catherine Zeta-Jones's hoofing in Chicago.
Also, it's difficult to say that Depp is held in the same regard as the other actors mentioned above. He's done a lot of crap, and it took a while for him to even be taken seriously. The Pirates sequels couldn't have helped his credibility, either.
).
