You actually can light up a course WAY better at night than dealing with flat light.
The key thing you're looking for is resolve. People need depth perception and the ability to see the nuances in all the stuff around them. Artificial light allows you to control this, and the X-games has a lighting budget bigger than Pink Floyd.
Daytime you can get hit with flat light, which is totally unbeatable. Putting dye on the landings helps a bit, but still nothing matches bathing things in pure bright sunlight.
As to the stiffness of landings, they have a super pro park crew there. Getting a solid grooming buff in before the finals would make all the landings perfectly soft and beautiful. You want firm landings, just not icy. Ever seen how the tiller on a snowcat works? It is like a gigantic rotating barrel with 6" spikes on it that drive into the snow breaking up the surface, and churning it up to be smooshed into beautiful corduroy.
TBH having finals at night is probably the best decision they could have made.