Even if the mountains were half that height, they would still be very high. For example the mountains I posted go all the way to the sky limit, and they aren't even in a mountain biome. I've never seen a mountain like that outside a mountain biome after 1.8. There also seem to be many more overhangs than in the normal worlds.
But yes, it is also possible that the hills just seem much higher now, or that I've got some lucky seeds.