Let me say upfront that while I have heard good things about the Nikon 85 f/1.4G, I do not have any first-hand experience with the lens. I am not an 85mm focal length kind of guy--for me this is the second (i.e. much less used) lens in a two or three lens travel kit. For that kind of usage, the extra 1/2 stop speed, weight and price of the f/1.4G vs. the f/1.8G were not attractive to me, and I've been very happy with the shots I get with the 1.8G. (The 35mm focal length is where I chose to step up.)
Since you specifically cite indoor/low light usage, the extra 1/2 stop may be the difference between getting the shot or not. If you need the f/1.4 aperture, then you need the f/1.4 aperture, and that's all there is to it. If cost is a factor, then I think a second-hand Nikon f/1.4D is not a lot more than the f/1.8G, and the f/1.4D is still highly regarded for its rendering of out-of-focus elements (I refuse to use the "b" word ).