If this is possible, I've seen it used for other games (train simulator, American truck sim, euro truck sim 2). Could there be categories for items? Cars, tracks, hud, series etc....
Arma 3 is another example of a organized Workshop. To be honest though, rF2 entire Steam page is poorly done. Unorganized Workshop, poor DLC description and lack of images.
I'll have a guide out soon on how to do it. Sadly, you can't just edit it on the workshop page, where it would be easiest.
It seems a lot of the workshop items are league skins. FILTERING those would be wonderful. Having a checklist for the user to hide items like fantasy tracks, or skins would be a great improvement.