Here's something I really didn't like about having 45 focus points when I had my 1DMkII- It was relatively difficult to choose the focus point you wanted, simply because there were so many of them. Easy enough to hit the assist button to get back to the center point, but I'll be damned if it didn't take a good few seconds to get to the upper left one that would be a simple, single touch of the joystick on my 5D. I switch focus points a lot, and it's gotta be easy. A few seconds can mean missing the shot. I could have MF'd, sure, but who knows how close I'd get.
Agreed for center on low light, if subject allows. I also only use manual exposure in very low light. It's just not worth risking otherwise.