Sleep isn't real.
I know this thread is dead, but it’s a damn interesting subject. The franchise has had its darker moments ever since the 80s, and G4 certainly isn’t one to stay away from it. However, I feel like the FIM is fine the way it is and pulls off saod scenes better than G1. Withv its explicitly dark or serious moments, it works for the most part and catches the viewer off guard (Fluttershy “breaking” Harry’s neck, Pinkamena Diane Pie, Twilight’s Kingdom, an the alrernate timelines from the season 5 finale). And hell, even some of the darker and more serious moments of the ahow are the subtle ones. What happens to the changelings victims, Luna coming to terms pretty much everybody she knew is dead, an earth pony making threats and nearly committing cold blooded murder, and the goddamn swamp filled with trees that might have been ponies once to name a few. The show is very capable of pulling off explicitly dark and serious scenes well, and even better when they have done them subtlety.