Never saw Logan, so I can’t speak for how watching it felt, but I can’t say it was the sort of thing that really interested me. Maybe that’s just because I can’t bring myself to care about the X-Men movies anymore, or Marvel as a company in general. Maybe you’re right though. It is apparently being toted as Hellboy: Rise of the Blood Queen, so it’s more likely than not going to pull a lot of elements from The Storm and The Fury arcs, which dealt pretty heavy in who Hellboy was and the deals he had to make to do what he needed to do. In this, I think Harbour makes a good addition, if his performance as Jim Hopper is anything to go by. That dude’s life was a fucking mess, but he seemed to take it in well enough stride, which is a very Hellboy thing to do.
The thing is, I’m not necessarily sure that having heavy themes really needs an R-rating, and I think setting a precedent that movies that have stronger emotional and ethical themes need one is probably bad idea. I’m standing by my idea that it restricts an audience that could benefit from heavier stories, namely teenagers. It’s true that they can just get their parents to take them, but the subject matter of Hellboy might make some parents balk, seeing as he is a huge red demon and people can get the wrong impression from that (which is pretty meta, if you think about it). So it’s better not to rely on that kind of tactic and just make it accessible to a younger audience that can choose for themselves to see it or not. R-ratings do legitimately keep an entire demographic out of movies, regardless of the blood and nudity contained.
A solid comic book movie can also serve the dual purpose of introducing would-be readers to the original material. Hellboy is incredibly easy to pick up, since it’s a lot more cohesive and coherent than mainstream comics. The more people who are able to watch it, the more potential new blood reading the series. I don’t think anything should be done to possibly limit that.