I could not disagree with you more. I'm a Realtor® and use this phone for business on a daily basis. The iP4 and the 3GS before it have replaced everything my Blackberry every did, and more. The proximity sensor is very sensitive to movement, so if you wiggle the phone or move it during your conversation you will have issues. This is something that will be fixed in software quite easily. In the meantime, just hit the lock button on top when in a phone call to avoid the issue.
No device is perfect. I suppose if you want perfection we should all return our iPhones and go for Android, right? NOT!
Ummmm so you have to have your hand PERFECTLY STILL to stay talking
Everyone moves a little when they talk, this is the weirdest reply I have seen about this issue so far.