Well i'm not sure you know this but gameplay=/=lore.
To be more exact the things the Champions due are not directly tied to lore any more. Such as Kindred causing a field in which no one dies, Nasus infinite stacks, or Alistar's ult. These things are not things the champions can do in the lore.
"But LANWhale! Shen uses his ult to travel to those in need, TF can teleport by using a card, and Azir can make sand soldiers!" in which I reply,"This is true, some abilities are canon but that doesn't mean their entire kit is canon." then you say,"That's confusing" and I reply,"I know it is son".
In other words the only things that I take canon in the game is the environment and the abilities that are used in stories. Which means the size of the champion in game isn't accurate.