looks fine in Civil War mostly, a lot of it has to do with lighting, angles, and CGI touch-ups. I'm not sure what story line will be told in the movie, but in reality, imagine the type of costume you would make if you were 15 years old, your parents died, you had super strength, and you were from NYC, and you were kinda poor (but not destitute). The above avg intelligence may help a bit, but not that much. It SHOULD look like a Halloween costume.
I see your point but I'd offer the counter that the movie is based on a fantasy world where a kid has super spider powers and being as it's not grounded in reality anyway the suit should look better than a cheap Halloween costume.