A good coach can make the difference between being mediocre and being a superstar. I've always viewed the drivers as the people who are physically executing the strategy, but it's up to the coach to guide them with that strategy. The drivers should be focusing on their robot only, the coach is their eyes on the rest of the field (and the clock). There are certainly different styles of coaches, varying from very talkative and direct to some that are more laid back and only direct when needed. This style should be tailored around what your drivers need out of a coach.
If you want to hear some cool opinions from 254s former drive coach, check out an interview Ty and I did with him earlier this year.
https://frcdesigns.com/2016/01/08/ke...vis-covington/
And if you have any specific questions, always feel free to ask!