Really though, isn't the function of the deflector dish to deflect space debris so it doesn't hit the ship? If so, I feel like that's a really dangerous thing to be messing with.
The main deflector or deflector array is crucial for stopping microscopic particles from wrecking most ships at relativistic speeds, and is technically called the "navigational deflector" for that reason.
At sub-light speeds those same particles are barely noticable, if at all, when stopped by the normal shields, basic deflectors or even hull plates. Which why they don't modify it while at warp, and pretty much only use it while at sub-light speeds.
In-universe it was designed to serve multiple purposes and be used in research or defense of other ships. And I seem to remember there being some sort of lockout where the ship wont go to warp if it can't engage the deflector. Since even a small particle cloud could destroy the entire ship a fraction of a second after it set off.
Voyager was especially notorious for this. TNG had its share of technobabble, but it felt like every character in Voyager apparently had intricate knowledge of advanced engineering concepts that magically solved every problem in almost every episode.
Chief Engineer B'Elanna: "There's this new problem no one has ever faced before and we don't know how to fix it!"
Commander Chakotay: "Have you tried realigning the dilithium matrix?"
B'Elanna: "It wouldn't work because it would cause an interference pattern in the warp attenuation field."
Chakotay: "What if we harmonize the polaron emitter to reverse the polarity of the chroniton field so we can convert the matter/antimatter reaction into a photonic gamma burst and triple the power of the warp core?"
B'Elanna: "That could work!"
Not real, but this feels like almost every episode in Voyager.
Like seriously... if these characters are all engineering geniuses do we really need a Chief Engineer or an entire department? Like some positions are starting to become redundant.
Data: Captain, we are being sucked in by an unidentified singularity. In approximately 1 minute 37 seconds our ship will be destroyed.
Picard: Modify the photon torpedos to emit a magnetic field. After that, lock onto them with a tractor beam while reversing the shield polarity of both the torpedos and our ship. While locked on, detonate them, causing a cascade reaction that allow us to safely entire a reverse warp bubble for 3.74 seconds.