2. It's Going To Be Huge
From the first trailer we already knew that there was likely to be at least one major set-piece, thanks to the helicopter gunship attack on Stark's home that resulted in a large portion of the architecture heading for a swim along with who we assumed was Iron Man (especially given the harrowing brief POV shot under water.) But now we now there will also be a second set-piece involving an air-plane disaster (the Dark Knight Rises similarities just continue to roll out), which will task Stark with saving 13 airborne victims, despite having the capabilities to carry only four. So either we're going to see a Sophie's Choice situation where Stark has to choose who to save, or an elaborate escape effort, which is certainly what appears to be implied in the trailer. Thankfully it seems Shane Black is going for size and impact in 3 - the real solution to the sequel question - and right now it looks like he might pull it off without the too-many-elements problems that faced Spiderman 3.