Sorry to hear it was such a bomb, considering the subject matter. Maybe someone will make a quality movie about that eventually.
A bomb? You're a tough judge. Fact is that Valkyrie has done quite well in terms of gross revenues (well abovea any films released since Jan 1), audience numbers, and critical reviews.
I thought the film was great. The best aspect was NOT being hollywoodized in terms of historical accuracy. The details were not tweaked or falsified to add typical Hollywood spices of sex, love, and other crowd -pleasing tidbits.
Cruise did an excellent job as Stauffenberg; his similar appearance was actually striking. He and the Hollywood AA voters are at odds and it is no surprise that he did not get a nomination, although I felt his performance was as good and interesting as most nominated. The film theme is also not a theme that Hollywood particularly likes--good Germans existing in the ranks of the Third Reich.