The first one was hands down a better flick than this one from a plot/story perspective
Well, as far as origin stories go, Favreau did a very commendable job with the original -- the only things I didn't like was how they changed the Rhodey/Stark backstory connection from the jungles of Vietnam to the deserts of Afghanistan (for modern-day purposes) as far as following the comics. I understand Favreau was going for a more up to date telling of the story, hence the first Iron Man's terrorists-in-the-desert-esque theme, but I always felt directors and filmmakers should keep these comic adaptations as close as humanly possible to their comic pedigree -- no matter how off the wall they may seem to audiences today, or how difficult it may be to do.
As for this sequel, I thought the Vanko/Whiplash "adaptation" was a bit hokey, as Favreau seemed to borrow themes of different villians for this, but the fight sequences between Rourke and Downey Jr. and Cheadle were amazing -- and that's what a comic adaptation is all about. I thought Favreau really drew us into the comic world of these characters in this one, although a few other things were way amiss outside of the aforementioned Vanko/Russian Whiplash thing...the whole sequence depicting Stark fighting Rhodes at his birthday party was just ridiculous and reminded me of the downright stupid Spider-Man 3 scene in which Peter enters the jazz club and goes nuts. Totally unnecessary (and I discussed this grave plot error with Gene privately). Then, there's the issue of how Stark got Captain America's shield in his workshop, and the goofy way the scene with Nick Fury (Samuel L. Jackson) and Stark plays when they're in the donut shop talking about SHIELD and such; it was just odd.
From what I understand, Favreau wants to do the Mandarin as the next villian -- as I discussed in the review -- but he's having a hard time visualizing how this character will play out in modern cinema, and how to bring him to life on the screen. Now that Disney seems to have acquired the Marvel Studios enterprise, they are going to be involved with The Avengers, Captain America and supposedly even Iron Man 3, so we have to see how everything comes to bear -- but it is indeed exciting to think that for the first time, we are going to get to see a group of superheros in a live-action major motion picture feature together at once.