Probably, most so called cult experts believe that Wahhabi groups tend to be cultic while Sufi groups are quite benign. However, there are Sufi cults which are usually neglected in anti-cult community.
I am not a Muslim, not a Sufi, and not a Wahhabi. I have no intention to promote any of those. However, I read both Sufi and Wahhabi literature and have some idea of what Sufism and Wahhabism are. In my opinion, Sufi teachings and practices may lead these groups to become cultic.
In the post Sufism: Shaikhs and Murids, I wrote about requirements for murids in their attitude toward shaikhs. As Muhammad Hisham Kabbani wrote, "The seeker [murid] must submit to the will of the shaikh and to obey him in all his orders and advice, because the shaikh has more experience and more knowledge in haqiqat, in tariqat and in shari'ah." And also: "He [murid] must agree with the opinion of his shaikh completely." Thus, murids are required to completely submit to their shaikhs in everything and to completely agree with their shaikhs opinions.
Murids are not allowed to question shaikhs' actions and words. Murids are not allowed to discuss their shaikhs' actions with other people. They are not allowed to speak negative things about their shaikhs. Murids are discouraged to leave their shaikh and go to another shaikh and are not allowed to go to more than one shaikh at the same time. All these requirements supposedly are for murids' spiritual benefit. Shaikhs supposedly have some special knowledge that they share with their murids and this knowledge is supposedly superior than what other Muslims have.
It is interesting that Bible-based abusive groups usually have somewhat similar rules of group members' behavior toward their leader while benign Bible-based groups usually do not have them. On the other hand, as far as I know, Wahhabi groups usually do not require their members to have such attitude toward their leaders. They criticize Sufis that they are submissive to their shaikhs and respect them so much.
In posts Sufi Practice of Collective Zikr and Sufi Practice of Singing Nashids / Nazams, I wrote about collective zikr and singing nashids / nazams and provided videos of these practices. In my opinion, outwardly, these practices have some similarities with some practices in video Captive Minds: Hypnosis and Beyond, that is, they may be trance-inductive. Sufi literature reports that many Sufis experience ecstasy when they do not realize what is going on around them and sometimes even say some things that a Muslim should not say. So, they do experience trance. Trans condition make people vulnerable to suggestions and cult leaders use it. It may take place in some Sufi groups as well. Wahhabi groups do not practice zikr and nashids. Moreover, they consider these things forbidden and blame Sufis because they practice them.
Therefore, I think that Sufi groups may potentially become cultic because they have prerequisites for that. I do not think that all the Sufi groups are cultic, but Sufi teachings and practices potentially may make Sufi groups cultic.