The second season of Agent Carter was far lower rated than the first, but a one-off special episode could drum up enough interest to bring in ratings that ABC could be proud of; however, the budget and timing would have to be right.
As for a potential future for Agent Carter, Hayley Atwell has still been championing the idea that her character could make another appearance on TV in the form of a special or something of that ilk.
Still, as Butters and Fazekas look to be sticking with ABC and Conviction looks as if it won’t get a second season in the fall of 2017, perhaps we’ll be in for a comeback at some point, although clearly this is just a hope at this point.