Wasn’t the 4 the first one with a “retina” screen? That was revolutionary at the time. Today, we take for granted high pixel density phones, but if you compared a 3GS to the new 4, it was mind blowing.
Yes, it was the first one with a retina screen. The change from the 3GS to the 4 was amazing. Also, the overall design was much slimmer. It seemed like a huge upgrade. Most of the upgrades since have felt much more incremental.