In a nutshell, our versions basically add more enemies and weapons and tweak everything a bit to make it more balanced. Just like the Trailblazer add-ons.
The worst-case scenario is 'Brutal Doom syndrome' where I go full drspam or DoomGuy007 and end up destroying this mod and getting myself banned. Don't get me wrong, weasel, I loved Nazis! and it's my top favorite of your works, but I just feel it's lacking in some areas and I thought I'd tune it up to make it renewed like it was released today.
But at the end of the day it's your work, and you get to ultimately choose what's in it.
I think my version will be a standalone due to the class-based player system and overhaul of items, weapons and enemies. Unless that can be counted as an add-on.
JOOC, exactly how many other editions of Nazis! are there? So far we have mine, CJ's, the one with the Indy Jones whip and armymen's (check his YouTube account).