Part of the issue of any time travel story as observed from the direction of an interest in alternate history is that they often operate on tantalizingly parallel, but still separate lines. If you can go back to the past and stomp around as much as you like without anything in the future changing, then what was the point of that to people who are fascinated by the idea of changing history? If you go back to the past and spend the whole time hiding and avoiding changing history because you're afraid of making yourself not exist or something, again, what was the point of that? You sit through all of, say, The Final Countdown waiting for the part where Kirk Douglas, Martin Sheen, and the USS Nimitz obliterate the Kido Butai with F-14s and A-7s, and then it just doesn't happen, and if that's what you wanted then that's maddening.
This is also the problem with more Man Who Came Early-type stories. It's an interesting story, a dark and sobering one about the gulf of time and ideas that separate us from the past, but as a time travel adventure piece, necessarily its not very good, because the adventure is a failure and he dies miserably. Getting out of the time machine to be greeted with 'Hey so did you meet that Hiller guy you were talking about? What was his deal? We're late for the rally, you can tell me on the way. Heil Himmler!' runs into the same problem with enough repetition.
EDIT: Of course all of those are better than some well-meaning but inattentive relative hearing you, a voracious adolescent reader, like time travel stories and gifting you a copy of Kindred by Octavia Butler for your birthday without knowing what it is actually about.