1.) What do you need?
I think we should think about requests later. First thing should be the (quite complicated) task of sifting through existing assets and figuring out who is going to contribute what and under what conditions.
My experience has taught me - build it and they will come.
I will build it and people will contribute or not. Building the best possible system is my priority, not the lowest common denominator. As with many decisions it'll be hit or miss.
This cannot be a majority decision, not even a democratic minority decision - I have no interest to remain in gridlock because the board of potential contributors cannot agree on how to contribute what and under which conditions.
Been there, tried it, failed, cured for life - sorry to be blunt.
Therefore I am happy to devour all suggestions, but ultimately I'll go the route I think it's best when looked at from the end user angle, the only angle that's worth looking at.
3.) How to structure everything?
I strongly favour d3:/textures/whitewolf/wallpanel simply because the alternative could easily become really messy. This method has the following benefits: you don't have the clusterfuck of renaming everything to fit a common standard. I'm all for standardisation but this is just impractical. You have textures/whitewolf/ and textures/BNA!/ and then everyone gets his own material file. Remember people use different naming conventions, ie I might use coolpanel_d for diffuse and you might use just coolpanel.tga or you might use coolpanel_bump instead of coolpanel_local.
set it up as d3w/textures/wallpanel/whitewolf - people want to find wallpanels, not whitewolves as textures
when they're searching. I thought about this on many different occasions for almost 10 years now and I am more than convinced any other attempt will fail. I've set up databases with millions of entries in my business and had to keep them failsafe, clean & searchable, I have proof what works, may the gods be with me so I can extrapolate that experience over a hobby board too. I should add, that the distribution folder naming should be reverse: textures/whitewolf/wallpanels/[files...] - I hope that clears up any misunderstanding, I didn't include that thought in my original post, sorry.
I however very strongly encourage double naming - d3w/textures/wallpanel/username/file AND!!! d3w/textures/username/walpanel/file . If someone says "nah, my may or the highway" then very fine - I strongly support strong opinions, even if they lead to self chosen excluding of ones work. Time will tell, if I'll get proven wrong, I'll adjust accordingly or hand it over.
When people are uploading a hundred textures, it starts getting to be a pain in the ass to sift through everything, update the material file, and test it. The mod owners have done this work already so why reinvent the wheel. The other thing is, people may upload under different licenses and yes copyright is important (remember the GPL uses copyright to work!).
People who want to work under different licensing options are free to do so. We'll either find a way to work out a system that suits their needs, or they'll create a version that fits the license. I want to help the community with an universally working solution, not build everything around special cases for people who are more diva than artist. Yes, I wrote more diva than artist - this wasn't a mistake.
I will introduce a system people can be very happy with, but I won't be able to please everyone.
In terms of "upload hundreds of textures and check them" - if someone is savy enough to mod, then he's more than equally capable to run a simple search and replace over one or more material files.
This really has to be kept to a minimum or there is going to be a splintering of assets under a gazillion licenses like sauerbraten. I would suggest at this point either CC Share-alike-attribution (which is basically the GPL for art assets) or the do-whatever-the-fuck-you-want license. (yes that is a real license.)
Well, I favor the "credit me and use it in non-commercial work or post your work elsewhere" license. Alternative & suggested options will get looked at incorporated if feasible.