DS9 s2e26 The Jem’Hadar
The cop-out explanation from Memory Alpha:
Only one Vorta was demonstrated using telekinesis: Eris. As the DS9 writing staff put more thought into the Vorta following their initial appearance in “The Jem’Hadar”, telekinesis was discarded and deemed a misstep that the writing team hoped viewers would forget. (Star Trek: Deep Space Nine Companion, p. 155) Ronald D. Moore stated, “Our internal rationale has been that Eris was given this ability for a specific purpose by the Founders (and maybe several other Vorta along with her) and that it is not a normal part of the Vorta ‘recipe’ in the Dominion.” (AOL chat, 1998) However, on an earlier occasion, Moore stated that other Vorta “presumably” had the ability, but no situations in which it would manifest had come up. (AOL chat, 1998)
Tbh, I like the explanation that they genetically engineered it into that ‘design’ of Vorta, but not others.
We know the Founders are seen as gods to the Jem Hadar (not just to Vorta), and yet the Founders still chose to make them reliant on ketracel white, just in case they overcame that ‘programming’ and rebelled.
Seems completely logical that they’d also limit the Vorta’s abilities in order to more easily curtail any future uprising too. Giving them all the ability to fire energy blasts could be something the Founders regretted later on.
It’s also true that the Federation’s first meeting with the Vorta was all orchestrated. It’s possible the energy blast is something they purposely show off during first contact to other powers, to act as a show of force to them.
As for plot lines that went nowhere in DS9, does anybody remember that there was initially a rift between Jem Hadar created in the Gamma Quadrant and those created in the Alpha Quadrant? It was shown in that episode where the defiant shrunk, but then was never mentioned again. They were clearly gearing up for a civil war plotline, but it never came to be.
I love it, there’s always a plausible in-universe explanation for anything if a trekkie thinks hard enough.