The sizes I gave are all from the Base sizes (1/2, 1, 2, 4 inch) The Giants are closer to Huge in height. Likewise, the Orog is 2" tall, but on a 1" base. The gargantuan Brass Dragon is on a 4" base, but the figure is closer to the size of the previous D&D Miniatures huge dragons.
It will make it harder to use them on a grid since huges control a 15x15ft space.