Instead of forcing them, we could suggest it to prospective contributors by adding a new sticky thread.
Something like:
You want to contribute? Look here!
With a link to the "need-to-HTL" shiplist or weapons.
...It happened in the past, that some artists could not finish their work for a myriad of reasons and in some cases the created assets were lost. To avoid this in the Future, we ask you to upload your WIP somewhere ( preferably to www.fsmods.net ) and post the link here, IF you decide, for whatever reason to not finish your Work. The entire community would be thankful.
As original creator of the asset, you will of course be credited.------------------------------------------------------------------------
Same goes for already released assets. In some cases, it'd be nice to have the original pre-conversion mesh ( UVed/ not UVed )
or PSD/ XCF file of a Ship texture or a Weapon effect or a Planet or what ever.
Those scenes and/ or PSDs should be uploaded to FSMods.net, to be available for people who want to use the assets, but want to modify it, or as a wysiwyg-tutorial.
Always assuming the original creator allows this.
As for the file formats, .MAX, .3DS, .Obj and .Blend for Models and .PSDs or .XCFs for Textures would be appreciated.
We could ask the owner of fsmods.net to create a category under Models for this purpose.
Just my 2 cents.