I thought with the first season, Hell On Wheels got off to a very engaging start. A possible widening revival of the American Western, even.
But at some point I just lost interest. Likely for the reasons you described, that I just stopped caring what happened to these characters. It's a tough balancing act in film and television, to create characters original enough to be interesting, but familiar (or clichéd) enough to be likeable so that viewers can identify with them.
Another thing that kills many shows is when they change creative staff from one season to the next, and that causes them to change the direction of the series in a very inconsistent and jarring way.
Some examples from a few series I like:
The excellent 1985 first season of Twilight Zone (with talented people like Harlan Ellison and Allan Brennert), that lost its staff (and its quality) in the second season.
And Buck Rogers In The 25th Century, where despite keeping the same cast, the producers completely changed the direction of the series to something insulting to viewers, and the series died about 10 episodes after the change.
Likewise the difference between the first and second seasons of the original Outer Limits series.
I don't know what the story was with Hell On Wheels, but regardless, it just wasn't the same series as when it started out.
