If you like character integrity, don't get into comics. Characters change constantly.
I don't think changing Spider-Man's sexuality would be bad change, though. It would create greater exposure for homosexuality in popular culture, which would hopefully lead to wider acceptance. But, like Billy Batson, I think it's mostly a moot point in terms of how it effects the character. He's still the same beloved, friendly neighborhood spider-man who believes that with great power comes great responsibility. He just likes a guy now instead of a girl. And I take issue with the fact that people object to or are appalled by the idea.
But, it's just a thought-experiment. It's NOT going to happen. Homosexuality hasn't received the level of acceptance in our society where having a bisexual super hero wouldn't hurt box office numbers. And, it's true, Sony wants to make money. If they didn't, they wouldn't have rushed into making Spider-Man in the first place, so soon after the last series.
Characters don't change that much over the years. Spider-Man has been around for a very long time, the general idea of the character is still there or I should say was before Superior Spider-Man, however Otto isn't Peter which is why there is such is a huge difference.
I think changing Spider-Man's sexuality WOULD be a bad change for him, I think you're underestimating the ignorance of the American public.