One of the big key points Jobs hit home again and again, was that its about 1 more phone call dropped per hundred. So how is it that this is such a big issue that people are experiencing if its clearly not a big issue.
Quite possibly lefties.
People who are left handed and making phone calls with the iPhone 4 will have greater signal loss than people who are right handed.
7% to 10% of the population is left handed.
If 7-10% of those dropped calls are from lefties, and that 1% additional dropped calls is from those lefties, then 1 out of 7 to 1 out of 10 of every left handed iPhone 4 user has experienced the problem.
They would also experience it more regularly. Which is why its such a big issue.