BTW the next Captain America is Titled " Captain America: The Winter Soldier " that too should tell you what it's bout.
Winter Soldier is a natural sequel to the first one.
Ultron...hmm. I'm a tad nervous, but its Joss at the helm, so should be okay. Why nervous? Because Marvel has some really over-the-top characters that tend to not translate well to the screen, nor interest the larger, non-fanboy audience. (Galactus, for example) To be fair, it will be an Ultron origin story, so the evolving character will not be at full strength, at least for most of the movie.
Also, Pym is not in this? Curious. I suppose Ultron will originate with Stark then. I wonder if it will be intended to be Jarvis 2.0.
He is getting a movie a couple months later, so they might leaves some holes to be filled in later. It would be nice to see some more continuity outside of the crossover movies (Iron Man 3 almost seemed to be trying to avoid mentioning what happened in Avengers out loud, even though those events had clearly changed everyone involved deeply and they kept using "New York" as a code word for Stark's PTSD), and since Thanos is supposed to have some role in three of the next four movies, they seem to be going that way.