I kind of like the positioning challenge that involves.
What positioning challenge? I have never seen AI ships attempt to maneuver around debris to get a shot off on a fighter squadron, and the player alone cannot meaningfully impact the rate of reclamation if more than one Fabricator is present.
Without it, swarms just mean doing a little bit more damage after killing a ship, with no extra strategy or thought.
Considering how the AI behaves I'm not so sure they would get the memo. Everything I've seen of their performance suggests to me that they would switch priorities to the nearest active Threat ship and focus on them, only shooting at the swarm from guns that don't have anything else in their arc. If the decomposing Threat ship in question has died completely separated from the group, with no other Threat ships nearby to distract its killer, maybe that
should be an easy cleanup. Most of the Threat ships that would die in such a way are probably the low-cost Skirmish units anyway, god forbid the Threat gets a 2%CR slap on the wrist for bad positioning once in a while.
I also disagree that there would be no thought to it. Making the decision whether to spend your damage on the six swarms flying off a decomposing Line unit or on an active enemy ship is more of a choice than we get right now, where shooting the swarms just isn't an option because the Line unit's hulk blocks them.
In any case I don't think that the swarms should lose HP
and decomposing ships should become intangible. I just think one or the other is worth experimenting with to see if it makes pursuing reclamation denial feel less like Charlie Brown trying to kick a football.