Keep it!
Software update wont fix the issue, but will ensure the bars displayed are more accurate etc.
Use the phone normally - I dont understand why people keep doing the 'death grip' in the first place - surely thats not how you would hold the phone under normal usage anyways? When I get mine I wont even test it that way, I'll use it normally (Im right handed anyway, which will help I guess!), and see how I get on.