This is not meant to sound like bragging or anything like that, but as I build fairly decent creations, and I am around people who build extremely authentic and detailed creations, whenever I see something that is not very good, it looks bad in my eyes.
What can you do to improve? Take a look at some good builders, and how they make fighters/spacecraft. You will learn something.
I don't think everything is mediocre, but I can tell you that this is plain 'not good'. You can improve on your own design to make it appealing to others. You are being very arrogant, and ignorant to say something is your own design, and you can't improve on it.