I have never had issues with accidentally brushing the trackpad because the palm detection is great. A large trackpad is a selling feature of the laptop.
Trackpad cursor is not 1:1 it moves farther the faster you move your finger. On default speed setting slowly moving the cursor from bottom left to top right of the screen uses up nearly the entire trackpad. In any case the point is that a big pad is not a downside because of detection, so for me it makes sense that it would be as big as there is enough space for.
Given how good palm detection is, does it matter? A large trackpad means more room for 4-finger gestures and less accidental triggering of the two-finger swipe-from-right-edge gesture.
I’ve had problems with the palm detection while typing. It’s great but it’s not perfect. I’d just rather have a trackpad like the previous gen. I wish they still sold it.
Legitimately I just tested moving around the screen. I am not using more than 3in x 2in at a time.