Final Fantasy XIV Producer Yoshida Naoki, or Yoshi-P, reveals in a new interview why the Summoner changes for Final Fantasy XIV Endwalker included removing DoTs. DoTs (damage over time) have been an integral part of the Summoner since its inception within FFXIV. However, the interview mentions that the removal of DoTs for the Summoner in FFXIV Endwalker was due to the sheer amount of Job Actions. [Thanks, ryokutya2089!]
That said, Yoshi-P is simply speaking about the various stages of re-tooling the Summoner Job Class to make it work in FFXIV Endwalker. Please keep in mind the translations are an excerpt from an upcoming issue of Famitsu, and are not complete.
Yoshi-P had this to say about the Summoner, and the conceptualization of this major change to the Job Class.
The Job Actions of the Summoner had reached its limits. It was barely possible to add new Job Actions, so we decided to do a massive overhaul with the release of 6.0.. The first concept of this overhaul was to remove all DoTs.
In September 2021, during a Letter From the Producer Live the development team explained that Summoner would see significant changes in Final Fantasy XIV Endwalker. This included the reveal that DoTs would be removed in favor of pet-focused actions.
Final Fantasy XIV is available for the PS4, PS5, and PC. Final Fantasy XIV Endwalker will release on December 7, 2021. Early access will begin on December 3, 2021. While the Summoner job class will be reworked in 6.0, currently people can use the character as a Primal-summoning DPS unit. Icy Veins offers a guide to the current version of it.