And as for the cheaper costume. The key to making something seem natural and real is imperfection. It's harder for me to respect something that seems so completely and utterly polished and showy and seeking approval. There's a falsness to it.
It's like the Hitman movie. Just the cover was enough to ruin it for me. I remember the character from the videogame being cold and cool. You had to respect his efficency. Then on the cover they have their rather soft looking actor in too much makeup with unatural lighting and touch ups, gazing into my eyes like he wanted to lure me to bed. Just another example of hollywood trying to pretty something up and completely neutering it in the process. So yeah, my point is that seeing spider-man in a cheaper costume will bring him closer to our world and make him seem less delicate and ornamental.
I don't think that comaprison to a well made costume is very apt at all. Comparing a guy wearing badly applied actor's make up with bad lighting is more akin to comparing it to a badly made awful looking, 'realistic' superhero costume, which is essentially what you want to replace the well designed one with. Because at the end of the day, it's all about what looks visually interesting and great onscreen.
With the movie Spider-man costume it's about trying to replicate the feeling you get when you look at a very well drawn and striking image from a comicbook.
This would not happen with the kind of costume you guys think you want.
So, to be more 'realistic', we should have a crappy looking, 'home made' costume, with no web definition, because that's what the guy would make in real life.
In real life he would wear what McGuire wore to the wrestling.
By this reasoning all Spider-man drawings should be of a guy with rips, patches and tears on his costume, baggy and saggy(when caught in wet weather for instance) , with a builder's ass hanging out of the trousers every now and again, after all that swinging and leaping about.
Or, if you want to ignore all the realistic things that would happen to his costume in real life and just settle for realistic stitching, you could just have a crappy looking tracksuit-like halloweeen suit, with the artist under instructions not to draw the webs in very well so you can barely see them.
Because that is what you are asking for, 'Make the costume look like crap please, as it would be more realistic!'
edit: and in fact, why not have crappy lighting following him around all the time? There's no film crew following Spidey around in 'real life', let's not only have a costume with webs you can't make out, let's not be able to make out Spidey very well either in general. Let's throw out the magic and illusion of moive making altogther and make it as realistic as possible, after all it's not like we need any kind of suspension of disbelief for these kinds of movies, or for movies in general right?
edit: and as for your argument about why they should not use organics... so they should not do certain things in sci-fi type fantasy movies because there is nothing in nature like it?!
How about they create a spider-man organic web shooter using a Spider's web and some kind of organic manipulation based on technology.
Sci-Fi is not bound by nature, sci-fi is subject to the imagination finding ways to further nature and technology through speculation.
edit: and anyway, if you mix up the spider DNA with a human's, you can speculate that the human part 'ejaculates' the web, sorry if anyone is reading this while eating their dinner, but that is the most obvious mix of human and spider nature to explain it.