When Apple makes a product with a serious defect... why do you want everyone to defect? Why is it ok for Apple to sell the defective product without dealing with it? Do you want all Apple products to have serious problems? Do you not care if Apple makes decent products? Do you want people to associate Apple with phones that can only make phone calls in strong signal areas?
What is your beef? Are you worried that you bought a product that people are complaining about? Is the product not 'cool' anymore, does that mean you're not 'cool'?
Why do people who do not have a problem get so worked up when folks who do have a problem with the new iPhone 4 talk about it?
If you don't have a problem great. You should be enjoying your fantastic phone. On the other hand, people who are experiencing a problem are complaining, trying to figure out more about the problem and in hopes that Apple will fix it.
I don't think everyone will defect because it doesn't affect most people in day to day use. The angry minority is the loudest, so it may seem like most people are unhappy, which is not true. I think every iPhone has this phenomenon so everyone is technically "affected" but not everyone cares. The very fact that most people still have their phones is evidence of that. If this problem were really that serious, people would be lining up to return their phones.
When I say "there is no issue", I don't mean I'm not experiencing this phenomenon. I am. But it's not an issue because it was intentionally designed that way. You can bet Apple field tested the hell out of the phone (in employees' houses, sans case). They found new phone gets much better reception than the 3GS normally but signal degrades if held a certain way. Apple thought it was worth the trade-off.
At this point, there are four options if you are unhappy: get a bumper, hold it differently, live with it, or return it. Most people here are not satisfied with any of these options and keep complaining in hopes Apple will fix it, which they might, but it's wishful thinking.
They've already denied the issue and if it were as simple as a software fix, they would've issued a statement saying, "We are aware of this problem and working on a fix." It would be a quick way to calm everyone down. Can you think of a reason they wouldn't say this if they had a fix? And for something that was intentionally designed that way?
So in the end, all this complaining will get you nowhere. I don't see how I'm being a fanboy when I advise returning the phone, which will hurt Apple's business. In fact, people returning the phone in droves be may the only way to get Apple to fix it.