From what I've seen, the following kinds of Hubs tend to get more comments - and sometimes "tons" of comments:
Hubs that strike a personal chord with a lot of readers - not just a few in the minority
Hubs that have strikingly beautiful photos, often of Nature - scenery or animals.
Images w/ super-cute or beautiful /well done crafts, home, art, other, projects.
Hubs that "push people's buttons" by discussing/suggesting/hinting at one political issue or another
Hubs that get a lot of traffic and/or comments and tend to make people think they'll get a little "publicity" for themselves by adding their Hubber name to the mix.
Hubs that appear commercially successful, which makes a lot of commercially-minded people think it's advantageous to them to get their name, and link if possible, on the Hub.
Hubs that tell of personal tragedy that is obviously not the fault of the author. These Hubs tend to bring out the supportive instinct in people.
Hubs that tell a multi-event/situation "hard-luck" story, as long as the Hub is not written in a way that suggests that author isn't looking for advice, guidance, or emotional support. As with tragedy, people tend to be supportive of what is clearly a hard-luck story; provided, however, the Hub/author don't make it clear that support and/or guidance is not what he seeks. People like people who want their guidance. They tend to dislike people who say, "No thanks. Your guidance isn't particularly what I need."
Hubs that essentially offer a lecture to "anyone the shoes fits" with regard to all the rules of living, character, and values that most of us were told, or figured out ourselves, in our childhoods, teens, or early twenties. With all those rules being very much accepted by most people, a good Hub about, for example, why people have to take responsibility for themselves or why people should make it a point to "not be selfish" and instead "be giving"; those Hubs tend to get a lot of readers who go on and do a "a whole rah rah" thing in support.
In other words, Hubs that point out perceived weaknesses and flaws in "a lot of" other people tend to get bandwagon-jumpers in comments. What won't get comments very well are often Hubs that involve a person's standing up for himself or not being willing to approach the Hub from an "It's so flawed," "I'm OKAY," or "It's not all my fault," angle. Many people tend to dislike, even hate, and/or ignore others who aren't looking for their support or guidance.