You don't fight very large people and very small people the same. It's an entire galaxy of reasons, from differing legal justifications (very unlikely that the force you need to stop an angry 100 kilo guy is the same force you need to stop an angry 40 kilo guy) to different angles (a foot difference in shoulder hight is a foot difference in the origin of all the hand strike attack angles) to different dead zone sizes and different access to the dead zones. The threat's lever arms are different lengths and the mass you need to control with those lever arms can vary widely.
It's not just that you take the skills in your weight class and take on someone three weight classes up and do your stuff harder or better or more. The things that work are qualitatively different.
Take the elbow leverage point, (what Al Arsenault calls, "the magic place"). At around my weight class I can reliably control the threat's entire upper body. Someone smaller, unless they have extraordinary rooting, I can get absolute control with one hand. But on an immensely strong or big threat, it takes all my structure to turn or to prevent him from turning and the wonderful control technique buys me time to get to someplace else and do something else.
And that's not all. If I have the edge in size and strength, I can work the elbow point with unidirectional power-- just push where I need the threat's shoulder (and then spine and pelvis) to go. With the super strong, I tend to shock-stop it and wait for the recovery power I know is coming and use that.
We all know this. If you have any exposure to judo at all you know that some throws are very difficult to make work against some body types, and some may be difficult depending on your own body type. Full-entry hip throws work great short-and-stocky versus tall-and-lanky but are hard to work the other way. The momentum throws tend to work great against strong, aggressive people in a fight, but not very well in matches at all.
Simple and obvious things-- whether you go over the humerus or under it to turn a body at close range is a matter of comparative height. So is the efficiency of working the back of the neck versus the chin. Head hunting on someone a foot or more taller is completely different (and loses a lot of efficiency).
There's more going on than just size or strength, or even just the threat's size and strength for that matter... but it's still one of those things so obvious that it might be missed.