Murder on the Orient Express

I finished this with a very skeptical look on my face. I'm not entirely sure how I feel about it. Engaging, sure, hence the three stars; I enjoyed reading it. But Poirot made some wild assumptions that made me give him the side-eye on more than one occasion. (I wanted to know why M. Bouc and Dr. Constantine escaped suspicion, in Poirot's eyes, given the limited number of people it could have been.) Am I allowed to say I just don't care for him as a detective much? The conclusion was not very satisfying, even though I didn't know whodunnit until the end.