Looks are obviously down to personal taste, I really like the iPhone 4 though, very 'industrial' when it was leaked & people said it was too ugly for Apple I quite liked it
I don't think Apple will take any massive leap like solar for quite some time, it wasn't a success for Samsung (?) & can be handled with solar powered cases/chargers for now so I don't think there is any rush.
I'm unsure what the next step to iPhone '4GS' is, screen will stay the same as it's still really good, processor might wait until iPhone 5 to swap over to iPad 2 chips so it doesn't really leave much to change apart from battery/camera/some internal chip no-one will use like wireless payments.
Mybe that's why they might not show one at WWDC & perhaps wait for the iPhone 5 this time?