Back when I was more into photography I was hearing about the importance of prime lenses for sharpness and focus. Apparently to get the best bokeh and aperture you need a prime lens.
I mean, when you think about it, for talking head videos and interviews, you don't need a zoom lens. Record with a prime and do your zooms in post because unless you have a camera operator, you won't be doing zooms anyway.
Though a 15-140mm would be nice, that way you get those wide angle frames while being able to get the zoomed shots you otherwise wouldn't be able to see in a pinch, and in some situations you don't want to be walking around with multiple lenses, and sometimes you don't have enough time to change lenses before the subject goes away.
In a studio I'd go prime. Out and about I'd go zoom.