Sizes in the game aren't equal to what's shown in animated stuff.

In the Black 2 and White 2 trailer, Lucario is shown to be at shoulder height with Nate despite being 3'11
In the same trailer Nate is shown to be as tall as his Emboar which is 5'03
In that same trailer Nate is shown to be taller than his Arcanine which is 6'03

Take this into account as well

While you may notice that Ash is short as hell while LT surge is really tall, the most important thing is that despite Raichu being only an inch short of being double Pikachu's height, it falls closer to 1 1/3rd of Pikachu's height.

That is one big electric sheep