To be honest, I kind of like the aspect where high value loot spawns need to be extracted with to sell. It is an interesting dynamic for what items to put in the secure container by judging which ones are still valuable to you without found in raid status. However when pvping, the majority of the good loot you can take off a killed player is not very good loot anymore.
I remember when I first started the game my solution to get over gear fear was to find a mid range kit that I was comfortable running that prioritized good ammo and armor and cost effective mods. Every time I would kill someone with a super meta kit I could sell most of the parts and gear on the flea market and it would regularly fund over 6 raids with my kit I was comfortable with. This doesn't happen anymore.
Now the number of kits you can pull out with you after a successful kill is basically just one, unless you prioritize the weapons over the other bits of gear, but even then you can probably only take 3 guns out, which are often less than half the cost of a full kit. The reason this value is so low now is because the only options are to either vendor the gun for a pathetic number of roubles compared to what guns used to be worth, or run back out with the guns yourselves, which as said is either a full kit or the gun half of 3 or so.
To me this feels like pvp encounters are not only being actively discouraged, but it also makes pvp encounters you end up in and succeed in much less satisfying. Really all you did was protect any loot you found so you can still have it found in raid, but the loot you get off the player is orders of magnitude lower in value. Hell, gunpowder on the flea market is worth more than a lot of full guns are vendored.
I'm not a game designer so I would not know what the best way to resolve this issue is. Obviously having items brought in by pmcs still count as found in raid is a risky proposition as it could enable cheesing quests in ways that the devs clearly don't want, but the general aspect of found in raid is a good addition in some ways. Would love to hear some discussion on this topic from anyone who has ideas on what BSG could do about this or if you don't think this is as big of an issue as I do.
Tl;dr not being able to sell weapon parts for high value on the flea after killing pmcs feels like it decentivizes pvp as loot from pmc kills is so much less valuable than it used to be when they can only be vendored or reused.