The most eloquent case for landscape without mountains that I know about is this poem by John Frederick Nims:
MIDWEST
Indiana: no blustering summit or coarse gorge;
No flora lurid as disaster-flares;
No great vacuities where tourists gape
Nor mountains hoarding their height like millionaires.
More delicate: the ten-foot knolls
Give flavor of hill to Indiana souls.
Topography is perfect, curio-size;
Tidy as landscape in museum cases.
What is beautiful is friendly and underfoot,
Not flaunted like theater curtains in our faces.
No peak or jungle obscures the blue sky;
Our land rides smoothly in the softest eye.
Man is the prominent fauna of our state.
Elsewhere circus creatures stomp and leer
With heads like crags or clumps. But delirious nature
Once in a lucid interval sobering here
Left (repenting her extravagant plan)
Conspicuous on our fields the shadow of man.
. . .
I personally am not against mountains, having loved living for three weeks in the shadow of Colorado's highest peaks, but I like the whole range of topography and would hate to hear of smaller mountains, bluffs, or knolls being slighted.