Sweet stuff on YouTube
This first clip is live action and cgi, and is about Mechwarrior.
This next clip is cut scenes from Heavy Gear, Armored Core, and Mechwarrior.
I found these clips to be a good illistration of size difference in mechs within a single game. All the combat scenes in the first one are good examples, and in the second at about two minutes and fifty seconds a Madcat finds itself face to face with an Atlas that is more than twice as tall.
Is the Atlas too big to play Mechwarrior with? No. Is the Madcat too small to play Mechwarrior with? No. Are they different scales? No, one is much larger than the other, but they exist in the same “game scale.”
Many Lego mech models that people chose to play Mechaton with will be taller than the “classic.” Does this invalidate them? No. Does it change the scale of the game? No, it does not have to, They can be larger because they are more powerfull, or they could be the product of a lower tech level, but of equal combat effectivness.