According to the dictionary defintion, a cult is a fanatical devotion to a human leader and/or a fad.
They have been around since the 1800s, so would they be a fad? As for a human leader, they worship Jehovah, or at least claim to. However, it is obvious they put a lot of trust into the WTS, a society that has made mistakes in the past.
Do I consider them a cult? ....I don't know. However, after reading the book called The Giver, for my Young Adult Lit class, my professor called the society in that book a dystopia. I saw some parallels between the society in The Giver, and the JWs. First of all, make three mistakes in Giver and you are executed. The JWs disfellowship, although that's not as extreme as execution. Second, you are assigned a job in the community in Giver; with the JWs, they don't want you to go to college, so your job selection is limited. Some of the people I've studied with have made subtle hints that I should drop college, my career plans, just to follow their group. I thought but didn't say "Go blow yourself. Pay for my stuff and THEN you can tell me what to do." Third, the community in Giver chooses a mate for you; the JWs seem to only allow baptized people to date each other, and I get the impression from adults of some girls that I'm not good enough for their daughter. Finally, the community in Giver seems perfect in a lot of ways. There are no wars(JWs stance of pacifism), everyone is assigned a role in the community, people are given drugs to make them happy and suppress sexual urges. etc. But really, it's a forced utopia, which makes it more of a dystopia. The JWs have a lot of good, but it's mostly forced.