I have nothing against him, I i fact like all the movies you listed, and him in all of them. But he's not "my" Vision. I trust Joss, so if he thinks it'll be great, then so be it. As far as how they'll work Pym in, my immediate assumption was that Ultron is JARVIS going rogue, or being hacked, and that Pym is brought it to BUILD Vision to help fight it.