I think this is a question best answered by you. It's mostly a matter of which lens you'd find more useful, and what can't be done well with the equipment you already have. You didn't say whether you have a full-frame or crop sensor camera, but I'm assuming FF, since the 16-35 is much less useful on a crop and there are lenses better-suited for less money.
You mentioned that your favorite subjects are landscapes, portraits and sports. What is it you do more of, and in what kind of situations do you find your current set-up most lacking? If you find yourself wanting something wider for sweeping views, I'd recommend the 16-35. On the other hand, if you'd rather have fast glass for low-light conditions and indoor sports, I'd say get the 1.2.
If I knew what you already own, I might be able to make a better call. What is your favorite lens now? And, is there something you have that you'd like to replace? Perhaps, if you can answer those two questions, you'll have your answer.
If it were up to me, I'd definitely get the 16-35. But, then again, I already have one.