KMFs are under 5 meters tall, the only mecha as small as them are King Gainer's Overmen.
Full Metal Panic's Arbalest is 8.5 meters.
Macross Frontier's VF-25F is 15.59 meters.
Gundams average 18 meters.
They will all stay in scale with each other as previous games have shown.
You can't compare the details of KMFs to Aquarion or Valkyries, both of them are originally highly rendered 3D CG mecha anime, they have lots of details. KMFs are designed to be easily drawn when animating them and they don't have too much detail.
Just look at the side by side:
