Happy to see we have some good topics for Zedkins.
I have experienced the lighting bug on LVS as well. As mentioned on the topic, it is fixable by just giving a block update, but if there is a long term solution for this that would be great. Creepers have surprised me on multiple occasions, in fully lit up areas. (It might be a 1.16 bug, idk)
I think the claimexplosions resetting to off is intended, it does it automatically if you leave the server, even for a server reboot. I personally like it that way, because I don't want to log on forgetting that I had it on and have things be blown up on accident.
As for the iron topic, I think I'm roughly in the middle of already set out positions here, but should mention I'm not overly fussed either way this goes. Piglin bartering
with iron nuggets, even if it was automatic, would not produce as much iron as a golem farm would unless you were to create a god-like gold farm - golem farms are ridiculously quick if you get them right. I think iron nugget bartering was added for a reason, and I don't really know why we would give up this if it is very intentionally a part of the game. I don't think golem farms are the same, as Mojang have tried to alter their mechanics in the past to nerf them. Finally, the iron isn't really free like they are in golem farms; you do have to trade gold. Gold is farmable though, so I guess compromises could be made to create a middle-ground solution.
I don't think many of the alternatives previously mentioned would solve this, but re-enabling nuggets* would. There are multiple compromises which could be made so this does not change things drastically:
Reducing chance of nugget drops, but still re-enabling them.
Reducing the number of max nuggets you can receive, but not reducing chance.
Only make nuggets obtainable if a player clicks the gold into the piglin's hand, so this is not a fully automatic farm.
Have some conditions which have to be met to allow piglins to drop iron nuggets, such as they only drop it during the same time villagers restock trades. (There are many options for this, just an example).