I assume downloaded/bought content is ok but don’t take my word for it. About the issue you are raising:
This content is not about how much love or work you put in creation of an asset or how complex and mindblowing your script is. It really is about what you make with whatever you have in ARK. It’s about the end result and how much gameplay value you created and added. I assume you also do not judge a game you buy by how much work hours they put in or which engine they used and how compatible the technology was towards their idea. Instead you judge the end product and the experience that got delivered. Please bear in mind that this is just my interpretation of the issue and Wildcard might see it different. Concerning your thought about previously existing Mods I would assume that they will judge the difference of what happened between the last submission and the current state.
I am not an artist but this sounds like you are creating an asset. My advice would be that you don’t care too much about how insanely epic and next-gen your asset looks but instead focus more on how much it adds to the experience.