Clear all floors in Savage for the mounts is a form of reward ... What kind of reward is it if everyone can get them ? Like others said, they lose their value. I don't wanna be rude but it looks like a whim. 12 mounts per expansion only with Savage contents ? It's huge.
I do Savage because I like it, and the mount is, among other things, a motivation for me to complete the fourth floor. I probably would not have the same motivation if I know that I can have one from the first floor, when the difficulty is close to an EX.