File this with UFO sightings. I agree that the sudden uptick in litigation reflects Apple being defensive but also paranoid to the fact that the iPhone can lose its edge as they transition to the post-Jobs era. Still, that doesn't suddenly make them underdogs as this article paints the picture. The massive user base ensures a stable upgrade market for some time. I'd be very afraid of Samsung too but Apple always had a feisty legal department (remember how they tried to shut down Apple rumor blogs long before the iPhone?) but they never shied away from out innovating competition.
Having said that, there's nothing technically remarkable about iOS 5 that combined with fancier hardware would make it more enticing to upgrade from iPhone 4 so far. I'm praying for surprise (like weather proof or charging via conduction).