first, adding an item is a LOT of labor to enter data that's freely available from amazon's APIs for most products you're going to encounter.
not only would this be _much_ easier if you just allowed me to paste in an amazon link, or name that you searched for on amazon, you could also easily generate affiliate links and make money. I used _my_ affiliate link for the product link because... why wouldn't I? except now that i look at the products i see there aren't any links? Why wouldn't you offer links to go buy these things, doubly so when you could profit from it AND make life easier for users without costing them anything.
obviously there needs to be a fallback mechanism to handle things that aren't sold on amazon.
you ask for a weight in kg or lb, thus suggesting a desire to cater to international audiences but then you don't have a currency for price.
"BIFL Score" is something i can guess but is never actually defined. Don't make users think.
when i submit it asks for an email address, but you already HAVE my email address from when i signed in. You could just make this a checkbox "do you want to be notified when we add this?"
Some products seem to have multiple categories but i could only select one. These seem conceptually like tags so i don't know why it's a pull-down instead of a multi-select or some other multiple choice thing.