Some mods completely redo the system of weapons, first and foremost Fallout 3 Wanderer's edition. How exactly did they do it?

I wanted to try to implement a new system of weapons using a new Weapon's Modifications Addon that I'm using, plus retextured models from New Vegas.

I'll post the idea the items I wanted to use once I've finished drafting it.

But what would be necessary to have certain weapons appear at certain levels on monsters, NPC's and Vendor's lists?

FWE folks would give a more complete and probably more correct answer.

I'll give it my best go.

Each weapon has stats some visible in game and some not visible in game. By adjusting these stats you change the behavior and value of the weapon. Of course FWE does much more than this as they address other aspects of the http://fallout.wikia.com/wiki/Damage.

I'm not sure if you can fiddle with all the stats using edit - you may have to open the GECK to get at all of them. They give a list of stats http://sites.google.com/site/fo3wanderersedition/reference/weapon-stats.

Of course FWE started as a collection of other mods listed http://sites.google.com/site/fo3wanderersedition/credits-contributors. One such mod is the Fallout Balance Overhaul by Xodarap777 - who I see made a version for NV.

Much further down the line they then started to implement FOSE to further tweak the damage formula with ingame menus. This makes it an extremely advanced overhaul for this game engine. I can't think of anyone else doing that except for a few scripted OBSE mods for Oblivion - and none of those provide in-game altering.

My request was that once they included FOSE scripting of weapon damage that they then revert all the weapons back to Vanilla style stats and let the scripts do the overhauling. This would allow for more compatibility. But, I guess the scripts can't handle all the varying stats and they wanted those other aspects of weapon stats included .... at least that is my understanding.

You can use Wrye Flash for F3 (and probably NV - though I've not even installed it yet) to export weapon stats from an esp/esm then have a spread sheet to look at which would make decisions and viewing easier than say scrolling through edit or entry by entry via the GECK. ... hmmm actually I've never used that with F3 only Oblivion so I could be wrong about it working.

Or you can attempt to do it all via scripts but that would likely mean globally or updates for each inclusion.

I look to be corrected on any of the above (I wouldn't be surprised if I got stuff wrong).

>>But what would be necessary to have certain weapons appear at certain levels on monsters, NPC's and Vendor's lists? <<

View Marks Balance mod available with his Wastland Patrols on Nexus. Though the mod is not meant to be played, it can be studied. He has a "tech quest" in there that starts EVERYBODY out with 32s then works up the scale. After a certain number of enemies are killed then the quest grants better weapons.

You simply set the level you want them to appear in the leveled list the weapon is in. It's not hard to do really. If you take a look at how leveled lists work you should be able to figure it out within minutes.