The issue here is whether the AF of the A7 series is sufficient for specific siutations where there lighting is not optimum. The key ingredient to the AF of the A7 series is contrast. Low light with some contrast on the subject matter will help, but the contrast will not always be on the area where the focus is needed. So depending on the lighting situation, you could get the shots you want with AF, but it is always the case. There are workarounds, and rightfully suggested that experience counts. One could always anticipate the focus point or apply their knowledge of DOF to figure out what and where an image will be sharp.
However, I question the idea that manual focus can always overcome the weakness of the AF of the A7 series, regardless of the level of experience. Experience can help under certain conditions, but these conditions generally limit the moment or opportunity. At the end of the day, a better AF system always wins.