This is an interesting post, I do believe that one day the best will be together to make the best MOD of all times.
About your idea it as some downsides:
1 There are specialised MODs ex: Desert Storm, Lost Brothers, BAS, Somalia,Falklands... It's natural that each ones of them, decides to have their own weapons.
2 As you know there are too many good addon makers to join them in one team, Russians,Brittish,Americans,French,Gemans (you name it) , (you count them),joining hundreds it's a little bit hard...
3 As you also know it's hard to make such a distinguish list to go along ;D
4 The freedom to choose what an addon maker feels like doing instead of what he has to do makes a big difference.
5 Some guy makes a pack of hand guns, and they are all there, well but I think I can make some better, and also I like to use only my work (for example) why shouldn't I make them and them give them to the community to have fun with them and decide which to use?
6 As you know addon makers keep on learning, desinging technics, modeling technics, cpp tricks, it's natural that addons tend to be updated, sometimes by the first ones who made it, other times by others.
7 The last one ;D when you go to a supermarket, you decide to buy some chocolate cookies, you prefer to have one type only, or a lot of types to choose? And even if for example, some are considered to be the best, you always have the right to don't like them, and prefer some others ;D
In away I understand your position, and as I told you, I do believe that one day the best will be together to make the best MOD the game as ever seen, and I mean everybody, sound makers, skinners, modelers, mission makers ...
But I'm also sure that quantity is a must in our community, it let's you choose which ones to download, instead of just having a "Here take it, if you don't like it fu** it, it's the only one, so you must like them".
My two cents opinion ;D