Actually, Red Mountain should be higher than High Hrothgar (Throat of the World), however it was really lame in Morrowind. I am sure in comparison the Throat of the World in TES V is larger than the Red Mountain in TES III, even though it shouldn't be.
Remember Daggerfall map size??
huuuuuuuuuuuugeeeee....
But it's not that big, according to those Tamriel maps...
I mean, it should've been about the same size as Oblivion... But it's much, much bigger...