Not really Anthony's fault. It's the writers'. He wasn't a character, he was set dressing, and the scripts treated him as such.
Though I agree with the totality of your post, I would especially like to say here, "I, agree." Anthony Montgomery wasn't given anything to do or work with on "Enterprise" Both he and Linda Park were done a real disservice by the writting. Blalock aside, they had a pretty talented group of actors who were repeatedly betrayed by the scripts they were given.