I'm personally hoping for some decent screentime during CA2 with Natasha, because the whole reason the Winter Soldier shows up is to kill her or to kidnap Steve. Steve brings Bucky back to his senses, and as an apology for the whole trying-to-kill-you thing, Bucky tells Natasha the reason he was sent out after her: after some years to recover from the USSR breaking up, they're starting up the Red Room again.

So then we've got the after-credit scene: Natasha heads to her quarters and starts packing, then whirls as she senses someone enter. She smiles as a matching black bag plops onto her bed, and the camera pulls back to show Hawkeye, in non-battle on-duty gear (think what he was wearing at the New mexico base).
"You don't have to do this," Natasha offers. "I do, but you don't."
"Yeah, I do," he smirks back. "You need to do this, and I need to watch your back doing it."
Natasha just smiles back at him, then the screen turns black to say: Natasha Romanoff and Clint Barton will return in "Black Widow: Dead on Target."
Said movie will be released between CA2 and Av2, during which all that lovely UST will be R'd. So Av2 opens with their first scene of the two of them being lovely and domestic - like Hawkeye making breakfast while Natasha packs away the guns off the kitchen table. While they're both in their pj's. (or just boxers for Jeremy, because - oh, c'mon, it's not like I have to explain around here...)