There is nothing more annoying than an image out of focus. The video below explains how modern day DSLR handles auto focusing. If you haven't noticed, brands like Nikon and Sony like to brag about how many hundreds of AF points they have on their cameras.
The important metric is not how many but what type of AF points and what aperture can the points can focus down to. I just came back from a wildlife photo shoot in India. Went there to photograph the Bengal tigers and Asiatic lions.
I brought along the Canon EOS-1D X Mark II and EOS-5Ds cameras on the trip. You can follow my travels on Facebook and Twitter , see my equipment bag and works on MichaelDanielHo.com