Even though i admit it is completely unreasonable to ask the devs to take spiders out of the game, I think it is pointless to put them in.
Spiders are something that will truly prevent arachnaphobic consolites without access to mods from buying the game.
Nobody sees a game and says "damn, no spiders, definately not buying it" but even though it is probably about 1% of the gamer population, there are people that would say "damn, loads of spiders, definately not buying it"
I don't think most people are scared to the point that seeing a spider in a video game scares them.. it's not even in 3D or anything, it won't jump out at you. Now, I dislike spiders greatly in real life (don't [censored] with spiders) but in games, meh. I just see it as the chance to express my hate by cleaving them in half with a sword!