Indeed NASA did bring a launchpad to the Moon; it's still there, together with further 5 launchpads of the other Apollo missions. They have been portrayed from orbit by Lunar Reconnaissance Orbiter.
Descent stage from orbit:
Ascent and descent stage coupled:
Descent stage (=launchpad for ascent stage):
Damage from regolite is a problem on the Moon: it was suspected, and then confirmed upon visually inspecting Surveyor 3 remains by Apollo 12's crew, which also brought back to Earth some Surveyor3 pieces for further analysis.
NASA did suspect this could be a problem while landing: this is why the landing procedure requires ideally a "virtual landing" (=0 vertical speed) at 5.6 feet (1.7m) above surface: this is the length of "foot probes", three booms hanging from LEM landing gear, which detect surface proximity by physically touching it and triggering a "contact light" onboard. The commander is supposed to shut off the engine upon this ground contact, to avoid damage from regolite.
Starting from 0 speed and accelerating at 1.62 m/s2, maximum terminal velocity on ground would be sqrt(2 * 1.62 * 1.7) = 2.3 m/s = 8.4 km/h
(Or you can also interpret this as "8.4 km/h will be added to the vertical speed at engine cutoff at 1.7 m altitude")