Doesn't work that way, you're forgetting that the same force applied over a greater area = less pressure, same force over greater area = more force at contact point.
It's a fine balance between keeping enough heat in the pad and not too much, granted smaller pads will create more heat due to higher pressure, all else being equal, but there's also less pad material to retain heat.
As a very rough rule the smaller/lighter the car the smaller the pad it can get away with, bigger pads could be used just not to their best, as won't get hot enough if a sporty pad.
Add to this some cars using aluminum discs and the whole pad material changes again, the way it is driven plays a big part of course.
The 1.4 astra auto I drive has greenstuff pads, but only 236mm discs, so fade nearly every day when I'm driving it, this is being swapped for 288mm vectra b discs with yellowstuff pads, on a car weighing around 930kg, but this is entirely down to my driving.
Having used yellows for years and my cossie all through 4 winters even ice snow etc I know they work ace when cold.
tabetha