Differences between "Troillus and Cressida" and the movie "Troy"

Having not read the “Illiad” (or having read it a long time ago and having forgotten), I am unsure as to whether the movie, "Troy," most closely resembled that version or Shakespeare’s, however, I can tell you where it strayed from the text.

The movie, “Troy,” starring Bradd Pitt, Orlando Bloom, and Diane Kruger (as Helen), was almost a reenactment of “Troillus and Cressida” by Shakespeare.  In Shakespeare’s play, the characters Troillus and Cressida are completely excluded from the movie.  This elision is most disappointing, because instead of watching a movie about the sadness of war, we watch a movie that glorifies it mostly since we hardly get any pangs of sadness from the ending of the movie—or at least I did not, anyway.  We do see the death of Aeneas and Achilles crying towards the end.  Another difference from the text is that Hector is completely defeated in a fair battle with Achilles, whereas, in “Troillus and Cressida,” Hector is literally stabbed to death while he is in a weak position. However, after reading online sources about the "Illiad," the director has kept most closely to the original text, whereas Shakespeare was the one who strayed.  

The omission of Cressida and Troillus just shows how much the director did not want to read further texts about the topic or explore hard-to-dramatize topics such as war and death.   (But let's assuming the director read most pertinent texts with regards to the Trojan war; his choice was clouded by the politics of the day, which would have been when George W. Bush was in power).