So here is my thought on the customization of weapons in this game…
I like it, but it needs to be done in a certain fashion for a game such as DB. Lets face it everyone likes to have a level of customization if not for any other reason besides making something a little more personal and making you stick out as “that player with the sweet swag!” EX: any Valve game with fancy hats other can see in game.
But we must remember this isnt a Valve game, its not dota with various skins, or csgo where you can pick up another persons gun and look at how fancy it looks (csgo has a look at gun button, bc you have time to waste int hat game)
In DB you would need something that can makes you feel like you are weilding something personal, yet unobtrusive enough it doesnt distract form the game besides the occasional player giving props on your sweet skin. Another thing to think about is the guns in DB as a bit more intricate and have more to them then the relatively flat sided guns in say csgo making designing them a bit trickier. I also think the crate and key drop with a random skin inside is a bit meehhhhh especially when actually money is involved.
As someone mentioned earlier there was a skin that made them colored like nerf toy guns, which IMHO great and it makes a stylistic FPS have a little bit more fun with itself. But if you change the actual model of the gun, say making one of the ARs look like a 90s super soaker, i think thats a bit too much. Reason being mercs can have a set of different guns and when you see that you identify what you need to do. If everything looks like a super soaker it confuses the fact.
As for modifications and customization for weapon attachments, ill leave that to the devs. Outside of anything cosmetic (different red dots for instance) there will need to be balancing in an already deep world.
As a side note since the game is also on steam, steam workshops can be integrated and used as a way to get the community involved. Although i said I wouldnt pay to open a crate for random skins, if there was a “community skins pack” where you get a bunch of nice skins for a couple of dollars, i would look into that. Reason being it supports the community, and i know what im getting as its not random.