Well, yes.
The thing I'm trying to get at is that unless you want technology to be entirely static and stagnant across centuries, there needs to be a plausible pathway for technological evolution. This is something you yourself have commented on- that it's a bit tricky to do this for Mass Effect, because of how little "wiggle room" you have to work with in terms of "I need to make this technology obviously inferior to that of the game era, but still recognizable as Mass Effect tech and capable of supporting interstellar civilization."
So I'm attempting to describe, not a path for technological evolution that has already happened, but for technological evolution that might happen.
And my point is that one predictable direction of evolution for torpedoes in particular is the introduction of nuclear shaped charges and/or bomb pumped laser designs.
For the reasons discussed, ship designers are unlikely to be truly content with their ships being sitting ducks for the first torpedo launched at them. "Under the hood" of what you have described happening in setting, there is presumably some attempt to create countermeasures to the nuclear torpedo. After all, engineers are not idiots, nukes are a threat, and if nothing else, salarians are not exactly known for technological conservatism or inability to innovate.
Obviously, for your desired narrative to be in play, the countermeasures against the nuclear torpedo cannot be perfect, and cannot even be all that good in the scheme of things... But it would be imposing artificial stupidity on your setting's factions (something you are usually loath to do without good cause) for the countermeasures to not exist.
Again, I wish to emphasize that countermeasures do not need to be perfect, just to exist, for this condition to be fulfilled. Even highly imperfect countermeasures are highly desirable. It makes a difference whether an incoming salvo of nuclear torpedoes scores two hits or four, and whether the warheads detonate 500 meters from the target's hull or 1,000 meters away, and so forth, and so on.
It seems to me that such attempts at countermeasures would logically exist, and can be integrated into the overall pattern of warfare. Even if in practice all they do is slightly blunt the otherwise terribly sharp sword of a torpedo attack, giving ships at best marginally better chances of survivability and continuing to fight than they would otherwise have.
Before I go further, may I ask whether you are agreeable to this proposition?
