I would return it correct. But not if the replacement is going to have the same issue. I do demand a product to work as advertised. I don't buy products that basically say, "well it works, but...".
A fully working product is a right. That's why we buy products. If you buy products that "work, but..." then that's your business. I expect it to work as advertised. Drop calls are a given with any cell phone. That I can accept. But having the phone not or drop signal simply because I place my hand over it is unacceptable. I shouldn't have change a way I hold my phone (a VERY unacceptable retort by Steve Jobs and completely ridiculous and an obvious indication of a design flaw). Maybe they should have advertised the phone needs to be held differently for this model. Because it sure hasn't been a problem for the last 3 years. Especially when I been buying and using iPhones since 2007.
You can defend Apple all you want. But this needs a fix and it needs to come fast.