I was actually speaking from more of a production/writing standpoint than the reasoning of Trask or any of the other characters of the film.

I think part of the reason they cut rogue out is because introducing her would pretty much poke a hole in the central plot to the movie.
A mutant's DNA leads to the downfall of humanity because it's used to create sentinels that possess a number of mutant like abilities which they can use to adapt to the mutant…