serious question: replace or not to replace?

It'll go away in a few days. Plus, you're holding it wrong

 

That's a tough one.. battery life is good on most phones so I wouldn't worry about that. However, no reception issues might be a hard one to give up for an exchange.. is reception in your area good? If so, might be worth a shot to exchange.. its a gamble and you'll have to decide.

My phone has a wobbly power button. I've exchanged before due to dust under the screen and noticed I'm just exchanging one problem for another so I've decided to just keep this phone since everything else is perfect.

 

Please stop with all these "you're holding it wrong" jokes, none of them are funny. I see them far too often and it drives me nuts!

Anyway OP I would book an appointment with a genius, if it's taken 3 weeks and the yellow blob still hasn't gone I don't think it will go anytime soon.
Even if you do receive a replacement phone which does have issues you can always return that. If I were you I'd want a perfect phone considering how much it costs.