Engineering main here.
As of now RCD is critical for engineer's efficiency.
There's a breach?
Slapping it with RCD takes 0.1s.
Making metal rods then metal floors and applying it in correct order takes like 5 seconds.
This gets elevated when you have to make new room for BSA.
Engineering is not that interesting department anyway. RCD makes it a lot easier and pleasant.
IMO RCD itself could be restricted to tech levels, and could be made in protolathe, but cardridges have to be available in autolathe. And the tech lvl would need to be low.
I cannot speak about the RCD balance as I am biased. RCD my beloved.
IIRC
@Miraviel made forum post couple months ago about changes in protolathe/autolathe/etc.
Cannot search it since I'm on phone. There were people talking about RCD me included. No idea if that post led to a PR on GitHub or not tho