One thing that is good about these super high resolution, fast primes is that when combined with high resolution camera bodies, such as the D810, there is quite a bit of flexibility in cropping which brings these lenses closer to zooms in practical use. I've noticed little damage to the quality of 200/2 II images when cropped by 1.5x in stage lit concerts and this gives added working range to the lens. I imagine the 105/1.4 should be similar. But the ability to do this crucially depends on how well the focusing works. If it is reliable and sufficient for the demands of depth of field at f/1.4, then the lens will be very useful also for event documentary images and not just portraits.
At weddings, I find myself often looking for medium telephoto lenses to pick audience / guest reactions to the speeches and program. The audience in the church can be in very low light, e.g. f/2, 1/125s, ISO 6400 is not atypical and places can be darker still. 1/125s is not a motion stopping shutter speed, but it usually allows relatively stationary reactions to be recorded sharply with the help of VR. Or, with an f/1.4 lens, at 1/250s which is already sufficient to stop most movement apart from sports etc. Although ISO 12800 has become usable in some of the latest camera bodies (D750, D5, D4 and Df) I still find the tonality thin and I would prefer to stay with lower ISO settings, but that really does require f/2 or f/1.4 lenses in some cases. I have reasonable amount of hope that the new 105/1.4 will focus fast enough, and above all, accurately so that it can be used for documentary photos in dim light as well as portraiture. If it turns out to be similar in AF performance to the 200/2 (II), I won't grind my teeth much. I still think they should make a 135mm as well, and in that case it should be at most f/1.8, or f/2, to avoid excessive cost and weight. Apo Sonnar image quality and Nikon SWM focusing - now that would be quite something.
