I didn't get this before seeing the movie and after having seen it, I still don't get this particular criticism. The only genuinely new characters introduced were Ultron and Vision. Quicksilver and Scarlet were introduced in The Winter Soldier.
If you're referring to Clint's family, sure, that was a surprise in and of itself, but I'm more interested in the fact, and I have no idea why I didn't piece this together before (wasn't paying attention), that he's not married to Mockingbird. It doesn't alter things too much as she's playing her role in AoS, and rightfully so, but that just.. bugs me.
I'll need some examples here. I had no trouble keeping up with things, but I will concede with things not being as fleshed out as they could, but it's the price paid for movies like this where there are multiple main characters - everyone doesn't get enough screen-time.
And I'm okay with that. Not really, but let's pretend that I am...
I see where both you and pm are coming from with this now, but the way I see it is there is a sense of continuity there but it's subtle: Stark wants Ultron to ultimately serve as a buffer, a means for them to not get involved unless absolutely necessary. Does it contradict 3? Yeah. I won't pretend that it won't, but that's how it came across to me.
I'd have to watch 3 again as everything after the original isn't exactly... memorable. I like 3 by itself and a hell of a lot more than 2 (and I actually dig 2), but wasn't the Christmas protocol or whatever he called it just a show-to for Potts that he wasn't going to obsess over it night and day, night and day, night and day, and be more focused on her?