Oedipal Automaton
The Ultron of the comics, built by Hank Pym, was often characterised by forms of father issues in relation to his creator. Though Pym’s own psyche was frequently explored within the panels of various series, I don’t believe that the chain of parental issues, which continued from Ultron in the other direction through the Vision, a rebellious invention of the villain, ever went back up along his way. Hank’s heritage was never really explored.
That’s why the cinematic universe’s placement of Tony Stark in the role of Ultron’s architect makes a bit of extra sense to me. This is a dude who already has father issues. His second movie was partially built around them. I can see how a robot programmed by a guy like that could end up with some Oedipal motivations.
His voice plays into that kind of psyche nicely too. As such personalities tend to rate their worthiness above that of their fathers even as they ignore flaws they may share with them, it seems appropriate for James Spader's Ultron to attempt to sound maturer than his creator in the midst of an arrogant swagger that matches Stark's.
The fact that he can also deliver archetypal comic villain lines is pretty great too. Seriously. He even does that thing of beginning a speech to the assembled heroes by speaking the team's name. So classic.
Bonus Question!
Quicksilver versus Quicksilver?
I probably caught some glimpse of Whedon's speedster around the release of "Days of Future Past", and I recall thinking that his version seemed less compelling from an aesthetic standpoint at least. As I watched the portrayal, however, I had no complaints, and the largely fabricated accent added a touch of extra flavour, though I'd give the larger share of the twins' style points to the female half of the duo. Scarlet Witch struts like a real chaos mage, and she deserves it. Even when Quicksilver isn't hitting the heights of mythic costumery, his is a solid look. His general design has never drifted too far from its original conception in the pages of the earliest "X-Men" books, and it was even recreated without any significant change for his Ultimate appearance, which is a rare feat that's even more notable in light of the attire's age. His sister has had a less steady relationship with fashion, which is why it's nice to see her make her cinematic debut with sartorial surety.
Anyway, I'd still give the win to Fox's Peter over this film's Pietro, and that can stand even if it is due in substantial part to an outfit that looks like the love child of Ramona Flowers's laundry hamper and a can of silver spray paint.