I personally don't think that Apple will redesign their iPhone. I think for the main reason of time. When this phone was found it was the end of April and it was just announced that WWDC was announced for early June. The reason I say this is that Apple has typically announced each new iPhone at the start of this conference they put on. So if they were to redesign the iPhone, they would have just about a month to redesign it and produce it. I am not a designer, but I would guess for something that is this popular, this would be too short of a time period. If anything, they may make some minor tweaks to it.

Although, you never know with Apple. They pride themselves on secrecy and being able to unveil amazing products. They will pull out all the stops to make this happen as well. So, who knows, they may do some drastic redesign and show off a prototype at WWDC and delay shipment till July or August so they can finish with the production of the redesign. But I wouldn't bank on this happening. I think the cost is too great for this at this point.

My hunch is that they will leave it the way it is, bite the bullet this time around and start selling it on the day they announce it at WWDC, so they can capitalize as much hype as possible. Hope this helps.