I really agree with you on that point. The The Times They Are Are a-Changin' intro is potent stuff. Deeply moving as well as incredibly effective in terms of conveying the back story. Gives me shivers just thinking about it.
I've read people really hating on the intro, but I definitely think it's close to the best bit of the film. It's an obvious song, but sometimes the obvious works really well, especially as most people don't actually listen to early Bob Dylan, they just absorbed the song through snippets. So actually hearing the whole thing, with those images, is very powerful.
In terms of the film, it does a nice job of displaying superheroes as morally bankrupt assholes. It doesn't do anything very profound or moving, and you could argue that it would be more effective if there was less bloat and slow-mo and more focus on the short sharp shock and the human, but it's certainly not a bad film. I'm currently watching Amazon series The Boys, which does the same thing with similar levels of violence, but isn't really any better, because it's hard to sculpt a moving human drama about crazy guys in funny suits.
The ending is problematic because while it's a neat idea, it is so bizarre and out of the blue, it does destroy the impact of any of the smaller-scale drama earlier in the film.
But in retrospect Watchmen was one of the first films to be killed by angry fanboys, and deserves a place in Hollywood history for that, if nothing else.