I always admire folks who know their history, and WED did some truly ground breaking work.
But let's also remember that WED (and Walt) plopped a 160 foot tall Swiss Matterhorn down in the middle of the park, where it looms over multiple lands and thematic stories that are anything but Swiss. Not to mention the eternal conundrum of how a Swiss mountain could be sitting next to a tropical lagoon with mermaids and atomic submarines going to the North Pole. I bet they had great office parties at WED in the 1950's and 60's, that's the only way to explain it!
Adding rocky cliffs beyond the berm on Disneyland's northern flanks will not be an issue. It'll make more sense than many other odd thematic twists installed in the park from 1955 to 1970.